diff --git a/app/Models/Category.ts b/app/Models/Category.ts
index 7f8255a..181ee29 100644
--- a/app/Models/Category.ts
+++ b/app/Models/Category.ts
@@ -1,16 +1,16 @@
+/* eslint-disable no-param-reassign */
+/* eslint-disable import/no-cycle */
 import { DateTime } from 'luxon';
-import { BaseModel, column } from '@ioc:Adonis/Lucid/Orm';
+import { nanoid } from 'nanoid';
+import { BaseModel, beforeCreate, column } from '@ioc:Adonis/Lucid/Orm';
 
 export default class Category extends BaseModel {
   @column({ isPrimary: true })
-  public id: number;
+  public id: string;
 
   @column()
   public title: string;
 
-  @column()
-  public slug: string;
-
   @column()
   public description: string;
 
@@ -19,4 +19,13 @@ export default class Category extends BaseModel {
 
   @column.dateTime({ autoCreate: true, autoUpdate: true })
   public updatedAt: DateTime;
+
+  /**
+   * Assign id to category by nanoid.
+   * @param category Category
+   */
+  @beforeCreate()
+  public static assignCategoryId(category: Category) {
+    category.id = nanoid();
+  }
 }
diff --git a/app/Models/Contact.ts b/app/Models/Contact.ts
index 91fe82a..b465aaa 100644
--- a/app/Models/Contact.ts
+++ b/app/Models/Contact.ts
@@ -6,7 +6,7 @@ export default class Contact extends BaseModel {
   public id: number;
 
   @column({ serializeAs: null })
-  user_id: string;
+  public user_id: string;
 
   @column()
   public email: string;
diff --git a/app/Models/Course.ts b/app/Models/Course.ts
index a554208..02dfd1b 100644
--- a/app/Models/Course.ts
+++ b/app/Models/Course.ts
@@ -1,9 +1,11 @@
 /* eslint-disable no-param-reassign */
 import { nanoid } from 'nanoid';
 import { DateTime } from 'luxon';
-import { BaseModel, beforeCreate, column, HasOne, hasOne } from '@ioc:Adonis/Lucid/Orm';
-import User from './User';
+import { BaseModel, beforeCreate, BelongsTo, belongsTo, column, HasMany, hasMany } from '@ioc:Adonis/Lucid/Orm';
 import Category from './Category';
+import Lesson from './Lesson';
+import User from './User';
+// eslint-disable-next-line import/no-cycle
 
 export default class Course extends BaseModel {
   @column({ isPrimary: true })
@@ -19,13 +21,22 @@ export default class Course extends BaseModel {
   public teacher_id: string;
 
   @column()
-  public category_id: number;
+  public category_id: string;
 
-  @hasOne(() => User)
-  public teacher: HasOne<typeof User>;
+  @belongsTo(() => Category, {
+    foreignKey: 'category_id',
+  })
+  public category: BelongsTo<typeof Category>;
 
-  @hasOne(() => Category)
-  public category: HasOne<typeof Category>;
+  @belongsTo(() => User, {
+    foreignKey: 'teacher_id',
+  })
+  public teacher: BelongsTo<typeof User>;
+
+  @hasMany(() => Lesson, {
+    foreignKey: 'course_id',
+  })
+  public lessons: HasMany<typeof Lesson>;
 
   @column.dateTime({ autoCreate: true })
   public createdAt: DateTime;
@@ -35,7 +46,7 @@ export default class Course extends BaseModel {
 
   /**
    * Assign id to course by nanoid.
-   * @param user User
+   * @param course Course
    */
   @beforeCreate()
   public static assignCourseId(course: Course) {
diff --git a/app/Models/Lesson.ts b/app/Models/Lesson.ts
new file mode 100644
index 0000000..65b27cb
--- /dev/null
+++ b/app/Models/Lesson.ts
@@ -0,0 +1,33 @@
+/* eslint-disable no-param-reassign */
+import { DateTime } from 'luxon';
+import { nanoid } from 'nanoid';
+import { BaseModel, beforeCreate, column } from '@ioc:Adonis/Lucid/Orm';
+
+export default class Lesson extends BaseModel {
+  @column({ isPrimary: true })
+  public id: string;
+
+  @column()
+  public course_id: string;
+
+  @column()
+  public title: string;
+
+  @column()
+  public description: string;
+
+  @column.dateTime({ autoCreate: true })
+  public createdAt: DateTime;
+
+  @column.dateTime({ autoCreate: true, autoUpdate: true })
+  public updatedAt: DateTime;
+
+  /**
+   * Assign id to lesson by nanoid.
+   * @param lesson Lesson
+   */
+  @beforeCreate()
+  public static assignLessonId(lesson: Lesson) {
+    lesson.id = nanoid();
+  }
+}
diff --git a/app/Models/Role.ts b/app/Models/Role.ts
index 241cf91..d9a1958 100644
--- a/app/Models/Role.ts
+++ b/app/Models/Role.ts
@@ -1,6 +1,7 @@
 /* eslint-disable import/no-cycle */
 import { DateTime } from 'luxon';
-import { BaseModel, column } from '@ioc:Adonis/Lucid/Orm';
+import { BaseModel, column, manyToMany, ManyToMany } from '@ioc:Adonis/Lucid/Orm';
+import User from './User';
 
 export default class Role extends BaseModel {
   @column({ isPrimary: true })
@@ -12,6 +13,11 @@ export default class Role extends BaseModel {
   @column()
   public slug: string;
 
+  @manyToMany(() => User, {
+    pivotTable: 'users_roles',
+  })
+  public users: ManyToMany<typeof User>;
+
   @column.dateTime({ autoCreate: true, serializeAs: null })
   public createdAt: DateTime;
 
diff --git a/config/cors.ts b/config/cors.ts
index dc0e3f6..ec98b5c 100644
--- a/config/cors.ts
+++ b/config/cors.ts
@@ -56,7 +56,7 @@ const corsConfig: CorsConfig = {
   |
   | Following is the list of default methods. Feel free to add more.
   */
-  methods: ['GET', 'HEAD', 'POST', 'PUT', 'DELETE'],
+  methods: ['GET', 'HEAD', 'POST', 'PUT', 'PATCH', 'DELETE'],
 
   /*
   |--------------------------------------------------------------------------
@@ -97,14 +97,7 @@ const corsConfig: CorsConfig = {
   | https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Access-Control-Expose-Headers
   |
   */
-  exposeHeaders: [
-    'cache-control',
-    'content-language',
-    'content-type',
-    'expires',
-    'last-modified',
-    'pragma',
-  ],
+  exposeHeaders: ['cache-control', 'content-language', 'content-type', 'expires', 'last-modified', 'pragma'],
 
   /*
   |--------------------------------------------------------------------------
diff --git a/database/factories/index.ts b/database/factories/index.ts
index de08b6b..5dc64ed 100644
--- a/database/factories/index.ts
+++ b/database/factories/index.ts
@@ -1 +1,49 @@
-// import Factory from '@ioc:Adonis/Lucid/Factory'
+import Factory from '@ioc:Adonis/Lucid/Factory';
+import Category from 'App/Models/Category';
+import Contact from 'App/Models/Contact';
+import Course from 'App/Models/Course';
+import Lesson from 'App/Models/Lesson';
+import User from 'App/Models/User';
+
+export const ContactFactory = Factory.define(Contact, ({ faker }) => {
+  return {
+    email: faker.internet.exampleEmail(),
+  };
+}).build();
+
+export const UserFactory = Factory.define(User, ({ faker }) => {
+  return {
+    first_name: faker.name.firstName(),
+    last_name: faker.name.lastName(),
+    login: `${faker.lorem.word(6)}${faker.datatype.number(10)}`,
+    password: faker.internet.password(6),
+  };
+})
+  .relation('contacts', () => ContactFactory)
+  .build();
+
+export const LessonFactory = Factory.define(Lesson, ({ faker }) => {
+  return {
+    title: faker.lorem.sentence(2),
+    description: faker.lorem.sentence(5),
+  };
+}).build();
+
+export const CategoryFactory = Factory.define(Category, ({ faker }) => {
+  const title = faker.lorem.word(6);
+  return {
+    title: `${title[0].toUpperCase()}${title.slice(1)}`,
+    description: faker.lorem.sentence(5),
+  };
+}).build();
+
+export const CourseFactory = Factory.define(Course, ({ faker }) => {
+  return {
+    title: faker.lorem.sentence(3),
+    description: faker.lorem.sentence(5),
+  };
+})
+  .relation('category', () => CategoryFactory)
+  .relation('lessons', () => LessonFactory)
+  // .relation('teacher', () => UserFactory)
+  .build();
diff --git a/database/migrations/1627022639849_contacts.ts b/database/migrations/1627022639849_contacts.ts
index ecd718a..8494fad 100644
--- a/database/migrations/1627022639849_contacts.ts
+++ b/database/migrations/1627022639849_contacts.ts
@@ -6,7 +6,7 @@ export default class Contacts extends BaseSchema {
   public async up() {
     this.schema.createTable(this.tableName, table => {
       table.increments('id');
-      table.string('user_id', 21).unsigned().references('users.id').onDelete('CASCADE');
+      table.string('user_id', 21).unsigned().references('users.id').unique().onDelete('CASCADE');
       table.string('email').unique().notNullable();
       table.string('phone_number').unique();
       table.string('vk_id').unique();
diff --git a/database/migrations/1627295886598_categories.ts b/database/migrations/1627295886598_categories.ts
index 99a5f91..c5a02d2 100644
--- a/database/migrations/1627295886598_categories.ts
+++ b/database/migrations/1627295886598_categories.ts
@@ -5,9 +5,8 @@ export default class Categories extends BaseSchema {
 
   public async up() {
     this.schema.createTable(this.tableName, table => {
-      table.increments('id');
+      table.string('id', 21).primary();
       table.string('title').notNullable();
-      table.string('slug').unique().notNullable();
       table.string('description');
       table.timestamp('created_at', { useTz: true });
       table.timestamp('updated_at', { useTz: true });
diff --git a/database/migrations/1627300211260_courses.ts b/database/migrations/1627300211260_courses.ts
index ce7df65..7044d45 100644
--- a/database/migrations/1627300211260_courses.ts
+++ b/database/migrations/1627300211260_courses.ts
@@ -9,7 +9,7 @@ export default class Courses extends BaseSchema {
       table.string('title').notNullable();
       table.string('description').notNullable();
       table.string('teacher_id', 21).unsigned().references('users.id').onDelete('CASCADE');
-      table.integer('category_id').unsigned().references('categories.id').onDelete('CASCADE');
+      table.string('category_id', 21).unsigned().references('categories.id').onDelete('CASCADE');
       table.timestamp('created_at', { useTz: true });
       table.timestamp('updated_at', { useTz: true });
     });
diff --git a/database/migrations/1627310102207_lessons.ts b/database/migrations/1627310102207_lessons.ts
new file mode 100644
index 0000000..76b3c9d
--- /dev/null
+++ b/database/migrations/1627310102207_lessons.ts
@@ -0,0 +1,20 @@
+import BaseSchema from '@ioc:Adonis/Lucid/Schema';
+
+export default class Lessons extends BaseSchema {
+  protected tableName = 'lessons';
+
+  public async up() {
+    this.schema.createTable(this.tableName, table => {
+      table.string('id', 21).primary();
+      table.string('course_id', 21).unsigned().references('courses.id').onDelete('CASCADE');
+      table.string('title').notNullable();
+      table.string('description');
+      table.timestamp('created_at', { useTz: true });
+      table.timestamp('updated_at', { useTz: true });
+    });
+  }
+
+  public async down() {
+    this.schema.dropTable(this.tableName);
+  }
+}
diff --git a/database/seeders/Category.ts b/database/seeders/Category.ts
deleted file mode 100644
index 3287e4e..0000000
--- a/database/seeders/Category.ts
+++ /dev/null
@@ -1,29 +0,0 @@
-import BaseSeeder from '@ioc:Adonis/Lucid/Seeder';
-import Category from 'App/Models/Category';
-
-export default class CategorySeeder extends BaseSeeder {
-  private Category: typeof Category;
-
-  public async run() {
-    this.Category = Category;
-
-    const category1 = new this.Category();
-    category1.title = 'JavaScript';
-    category1.slug = 'javascript';
-    category1.description = 'Category 1 description';
-
-    const category2 = new this.Category();
-    category2.title = 'ReactJS';
-    category2.slug = 'reactjs';
-    category2.description = 'Category 2 description';
-
-    const category3 = new this.Category();
-    category3.title = 'NodeJS';
-    category3.slug = 'nodejs';
-    category3.description = 'Category 3 description';
-
-    await category1.save();
-    await category2.save();
-    await category3.save();
-  }
-}
diff --git a/database/seeders/Course.ts b/database/seeders/Course.ts
index b0a6602..79bc1b9 100644
--- a/database/seeders/Course.ts
+++ b/database/seeders/Course.ts
@@ -1,53 +1,19 @@
 import BaseSeeder from '@ioc:Adonis/Lucid/Seeder';
-import Category from 'App/Models/Category';
-import Course from 'App/Models/Course';
 import User from 'App/Models/User';
+import { CourseFactory } from 'Database/factories';
 
 export default class CourseSeeder extends BaseSeeder {
-  private Course: typeof Course;
-
   private User: typeof User;
 
-  private Category: typeof Category;
-
   public async run() {
-    this.Course = Course;
     this.User = User;
-    this.Category = Category;
 
-    const teacher = await this.User.findByOrFail('login', 'nikolai123');
+    const teacher = await this.User.query()
+      .preload('roles', q => q.where('slug', 'teacher'))
+      .firstOrFail();
 
-    /**
-     * Course 1
-     */
-    const category1 = await this.Category.findByOrFail('slug', 'javascript');
-    const course1 = new this.Course();
-    course1.title = 'Course 1';
-    course1.description = 'Course 1 description';
-    course1.teacher_id = teacher.id;
-    course1.category_id = category1.id;
-    await course1.save();
-
-    /**
-     * Course 2
-     */
-    const category2 = await this.Category.findByOrFail('slug', 'reactjs');
-    const course2 = new this.Course();
-    course2.title = 'Course 2';
-    course2.description = 'Course 2 description';
-    course2.teacher_id = teacher.id;
-    course2.category_id = category2.id;
-    await course2.save();
-
-    /**
-     * Course 3
-     */
-    const category3 = await this.Category.findByOrFail('slug', 'nodejs');
-    const course3 = new this.Course();
-    course3.title = 'Course 3';
-    course3.description = 'Course 3 description';
-    course3.teacher_id = teacher.id;
-    course3.category_id = category3.id;
-    await course3.save();
+    await (await CourseFactory.with('category').with('lessons', 3).create()).related('teacher').associate(teacher);
+    await (await CourseFactory.with('category').with('lessons', 2).create()).related('teacher').associate(teacher);
+    await (await CourseFactory.with('category').with('lessons', 1).create()).related('teacher').associate(teacher);
   }
 }
diff --git a/database/seeders/MainSeeder/Index.ts b/database/seeders/MainSeeder/Index.ts
index c8a7e53..53e1e56 100644
--- a/database/seeders/MainSeeder/Index.ts
+++ b/database/seeders/MainSeeder/Index.ts
@@ -19,7 +19,6 @@ export default class IndexSeeder extends BaseSeeder {
   public async run() {
     await this.runSeeder(await import('../Role'));
     await this.runSeeder(await import('../User'));
-    await this.runSeeder(await import('../Category'));
     await this.runSeeder(await import('../Course'));
   }
 }
diff --git a/database/seeders/Role.ts b/database/seeders/Role.ts
index dcde9ba..76f7b15 100644
--- a/database/seeders/Role.ts
+++ b/database/seeders/Role.ts
@@ -1,10 +1,13 @@
-/* eslint-disable class-methods-use-this */
 import BaseSeeder from '@ioc:Adonis/Lucid/Seeder';
 import Role from 'App/Models/Role';
 
 export default class RoleSeeder extends BaseSeeder {
+  private Role: typeof Role;
+
   public async run() {
-    await Role.createMany([
+    this.Role = Role;
+
+    await this.Role.createMany([
       {
         name: 'Administrator',
         slug: 'admin',
diff --git a/database/seeders/User.ts b/database/seeders/User.ts
index 3dd2a66..0ca0c4f 100644
--- a/database/seeders/User.ts
+++ b/database/seeders/User.ts
@@ -1,12 +1,12 @@
 /* eslint-disable class-methods-use-this */
 import BaseSeeder from '@ioc:Adonis/Lucid/Seeder';
 import Role from 'App/Models/Role';
-import User from 'App/Models/User';
+import { UserFactory } from 'Database/factories';
 
 export default class UserSeeder extends BaseSeeder {
   public async run() {
     /**
-     * Roles
+     * Get roles
      */
     const roles = {
       admin: await Role.findByOrFail('slug', 'admin'),
@@ -17,40 +17,19 @@ export default class UserSeeder extends BaseSeeder {
     /**
      * Administrator
      */
-    const user1 = new User();
-    user1.first_name = 'Ivan';
-    user1.last_name = 'Ivanov';
-    user1.login = 'ivan123';
-    user1.password = 'ivan123';
-
-    await user1.save();
-    await user1.related('roles').attach([roles.admin.id]);
-    await user1.related('contacts').create({ email: 'ivan_ivanov@ya.ru' });
+    const userAdmin = await UserFactory.with('contacts').create();
+    await userAdmin.related('roles').attach([roles.admin.id]);
 
     /**
      * Teacher
      */
-    const user2 = new User();
-    user2.first_name = 'Nikolai';
-    user2.last_name = 'Nikolaev';
-    user2.login = 'nikolai123';
-    user2.password = 'nikolai123';
-
-    await user2.save();
-    await user2.related('roles').attach([roles.teacher.id]);
-    await user2.related('contacts').create({ email: 'nikolai_niko123@ya.ru' });
+    const userTeacher = await UserFactory.with('contacts').create();
+    await userTeacher.related('roles').attach([roles.teacher.id]);
 
     /**
      * Student
      */
-    const user3 = new User();
-    user3.first_name = 'Oleg';
-    user3.last_name = 'Olegov';
-    user3.login = 'oleg123';
-    user3.password = 'oleg123';
-
-    await user3.save();
-    await user3.related('roles').attach([roles.student.id]);
-    await user3.related('contacts').create({ email: 'oleg_olegov123@ya.ru' });
+    const userStudent = await UserFactory.with('contacts').create();
+    await userStudent.related('roles').attach([roles.student.id]);
   }
 }