Added Post and Image entities to the database.

backend/libs/database/image.entity.ts

@@ -0,0 +1,24 @@
+import { Entity, PrimaryColumn, Column, OneToOne, JoinColumn } from 'typeorm';
+import { Post } from './post.entity';
+
+@Entity()
+export class Image {
+    constructor(props?: Partial<Image>) {
+        Object.assign(this, props);
+    }
+
+    @PrimaryColumn()
+    message_id: number;
+
+    @Column({ nullable: false })
+    post_id: number;
+
+    @Column({ nullable: false })
+    file_id: string;
+    @Column({ default: false })
+    has_spoiler: boolean;
+
+    @OneToOne(() => Post)
+    @JoinColumn({ name: 'post_id' })
+    user: Post;
+}