fix: add revised migration

src/entities/User.ts

@@ -4,21 +4,29 @@ import { Link } from "./Link"
 @Entity("users")
 export class User {
 
+	// Unique user id.
 	@PrimaryGeneratedColumn()
 	id: number
 
+	// User name, must be unique.
 	@Column({ unique: true })
 	name: string
 
+	// Salted password hash.
 	@Column()
 	passwordHash: string
 
+	// User role:
+	// - 0 - means unprivileged user,
+	// - 1 - means administrative user.
 	@Column()
-	role: string
+	role: number
 
+	// Account creation date as a Unix timestamp.
 	@Column('bigint')
 	createdAt: number
 
+	// List of shortened URLs which belong to the user.
 	@OneToMany(() => Link, (link) => link.author)
 	links: Link[];
 }