Improve sql

persistance/src/main/kotlin/users/UserRepositoryImpl.kt

@@ -11,8 +11,13 @@ import java.sql.SQLIntegrityConstraintViolationException
 internal class UserRepositoryImpl(private val db: Database) : UserRepository {
     override fun create(user: User): PersistedUser? {
         return try {
-            db.useTransaction { db.users.add(user.toEntity()) }
-            find(user.username)
+            db.useTransaction {
+                val id = db.insertAndGenerateKey(Users) {
+                    it.username to user.username
+                    it.password to user.password
+                } as Int
+                PersistedUser(user.username, user.password, id)
+            }
         } catch (e: SQLIntegrityConstraintViolationException) {
             null
         }
@@ -22,5 +27,5 @@ internal class UserRepositoryImpl(private val db: Database) : UserRepository {
     override fun find(id: Int) = db.users.find { it.id eq id }?.toPersistedUser()
     override fun exists(username: String) = db.users.any { it.username eq username }
     override fun exists(id: Int) = db.users.any { it.id eq id }
-    override fun delete(id: Int) = db.useTransaction { db.users.find { it.id eq id }?.delete() == 1 }
+    override fun delete(id: Int) = db.useTransaction { db.delete(Users) { it.id eq id } == 1 }
 }