Implement backend API and database services in Docker setup

- Added a new `api` service for the NestJS backend, including health checks and dependencies on PostgreSQL, Redis, and MinIO.
- Introduced PostgreSQL and Redis services with health checks and configurations for data persistence.
- Added MinIO for S3-compatible object storage and a one-shot service to initialize required buckets.
- Updated the Nginx configuration to proxy requests to the new backend API and MinIO storage.
- Enhanced the Dockerfile to support the new API environment variables and configurations.
- Updated the `package.json` and `package-lock.json` to include new dependencies for QR code generation and other utilities.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/src/discounts/entities/discount.entity.ts

@@ -0,0 +1,103 @@
+import { Content } from 'src/contents/entities/content.entity';
+import { DiscountRedemption } from 'src/discount-redemption/entities/discount-redemption.entity';
+
+import {
+  Entity,
+  Column,
+  ManyToOne,
+  OneToMany,
+  CreateDateColumn,
+  UpdateDateColumn,
+  JoinColumn,
+  DeleteDateColumn,
+  PrimaryColumn,
+} from 'typeorm';
+import {
+  DiscountType,
+  DiscountTypes,
+} from '../constants/discount-type.constant';
+import { User } from 'src/users/entities/user.entity';
+import { Season } from 'src/season/entities/season.entity';
+
+@Entity('discounts')
+export class Discount {
+  @PrimaryColumn()
+  id: string;
+
+  @ManyToOne(() => Content, (content) => content.discounts, {
+    nullable: true,
+    onDelete: 'CASCADE',
+  })
+  @JoinColumn({ name: 'content_id' })
+  content: Content | null;
+
+  @Column({ type: 'varchar', nullable: true })
+  contentId: string | null;
+
+  @ManyToOne(() => Season, (season) => season.discounts, {
+    nullable: true,
+    onDelete: 'CASCADE',
+  })
+  @JoinColumn({ name: 'season_id' })
+  season: Season | null;
+
+  @Column({ type: 'varchar', nullable: true })
+  seasonId: string | null;
+
+  @Column({ type: 'varchar', length: 50, nullable: false })
+  couponCode: string;
+
+  @Column({
+    type: 'decimal',
+    precision: 5,
+    scale: 2,
+    nullable: false,
+    transformer: {
+      to: (value) => value,
+      from: (value) => Number.parseFloat(value),
+    },
+  })
+  value: number;
+
+  @Column({
+    type: 'varchar',
+    length: 20,
+    default: DiscountTypes.PERCENTAGE,
+  })
+  type: DiscountType;
+
+  // Start date (null = no start date)
+  @Column({ type: 'timestamp', nullable: true })
+  startDate: Date | null;
+
+  // End date (null = no expiration date)
+  @Column({ type: 'timestamp', nullable: true })
+  expirationDate: Date | null;
+
+  // Total usage limit (null = unlimited)
+  @Column({ type: 'int', nullable: true })
+  maxUses: number | null;
+
+  @Column({ type: 'varchar', length: 255, nullable: true })
+  email: string | null;
+
+  @OneToMany(() => DiscountRedemption, (redemption) => redemption.discount)
+  redemptions: DiscountRedemption[];
+
+  @ManyToOne(() => User, { nullable: false })
+  @JoinColumn({ name: 'created_by_id' })
+  createdBy: User;
+
+  @Column({ type: 'varchar' })
+  createdById: string;
+
+  @CreateDateColumn()
+  createdAt: Date;
+
+  @UpdateDateColumn()
+  updatedAt: Date;
+
+  // Soft delete
+  @DeleteDateColumn()
+  deletedAt: Date | null;
+}