feat: チャンネルをお気に入りに登録できるように

Resolve #10097

packages/backend/src/models/entities/ChannelFavorite.ts

@@ -0,0 +1,41 @@
+import { PrimaryColumn, Entity, Index, JoinColumn, Column, ManyToOne } from 'typeorm';
+import { id } from '../id.js';
+import { User } from './User.js';
+import { Channel } from './Channel.js';
+
+@Entity()
+@Index(['userId', 'channelId'], { unique: true })
+export class ChannelFavorite {
+	@PrimaryColumn(id())
+	public id: string;
+
+	@Index()
+	@Column('timestamp with time zone', {
+		comment: 'The created date of the ChannelFavorite.',
+	})
+	public createdAt: Date;
+
+	@Index()
+	@Column({
+		...id(),
+	})
+	public channelId: Channel['id'];
+
+	@ManyToOne(type => Channel, {
+		onDelete: 'CASCADE',
+	})
+	@JoinColumn()
+	public channel: Channel | null;
+
+	@Index()
+	@Column({
+		...id(),
+	})
+	public userId: User['id'];
+
+	@ManyToOne(type => User, {
+		onDelete: 'CASCADE',
+	})
+	@JoinColumn()
+	public user: User | null;
+}