feat(department): add column of code for department

src/entity/department.ts

@@ -7,6 +7,13 @@ export class Department {
     @PrimaryGeneratedColumn("uuid")
     id: string;
 
+    @Column({
+        nullable: true,
+        length: 64,
+        unique: true,
+    })
+    code: string;
+
     @Column({
         nullable: false,
         length: 128,