Add PostgreSQL-backed data storage support (#444)

Co-authored-by: samanhappy <samanhappy@gmail.com>

src/db/entities/UserConfig.ts

@@ -0,0 +1,33 @@
+import {
+  Entity,
+  Column,
+  PrimaryGeneratedColumn,
+  CreateDateColumn,
+  UpdateDateColumn,
+} from 'typeorm';
+
+/**
+ * User configuration entity for database storage
+ */
+@Entity({ name: 'user_configs' })
+export class UserConfig {
+  @PrimaryGeneratedColumn('uuid')
+  id: string;
+
+  @Column({ type: 'varchar', length: 255, unique: true })
+  username: string;
+
+  @Column({ type: 'simple-json', nullable: true })
+  routing?: Record<string, any>;
+
+  @Column({ type: 'simple-json', nullable: true })
+  additionalConfig?: Record<string, any>;
+
+  @CreateDateColumn({ name: 'created_at', type: 'timestamp' })
+  createdAt: Date;
+
+  @UpdateDateColumn({ name: 'updated_at', type: 'timestamp' })
+  updatedAt: Date;
+}
+
+export default UserConfig;