feature #9: Add security for route "create article"

src/main/kotlin/fr/dcproject/repository/User.kt

@@ -3,6 +3,7 @@ package fr.dcproject.repository
 import fr.postgresjson.connexion.Requester
 import fr.postgresjson.repository.RepositoryI
 import io.ktor.auth.UserPasswordCredential
+import java.util.*
 import fr.dcproject.entity.User as UserEntity
 
 class User(override var requester: Requester) : RepositoryI<UserEntity> {
@@ -16,4 +17,16 @@ class User(override var requester: Requester) : RepositoryI<UserEntity> {
                 "plain_password" to credentials.password
             )
     }
+
+    fun findById(id: UUID): UserEntity {
+        return requester
+            .getFunction("find_user_by_id")
+            .selectOne(
+                "id" to id
+            ) ?: throw UserNotFound(id)
+    }
+
+    class UserNotFound(override val message: String?, override val cause: Throwable?): Throwable(message, cause) {
+        constructor(id: UUID): this("No User with ID $id", null)
+    }
 }