feat: BAC-39 Authentication (#114)

Reviewed-on: #114
Co-authored-by: Janis <janis.e.20@gmx.de>
Co-committed-by: Janis <janis.e.20@gmx.de>

knockoutwhistweb/app/di/EntityManagerProvider.scala

@@ -0,0 +1,22 @@
+package di
+
+import com.google.inject.Provider
+import com.google.inject.Inject
+import jakarta.inject.Singleton
+import jakarta.persistence.{EntityManager, EntityManagerFactory, Persistence}
+
+@Singleton
+class EntityManagerProvider @Inject()() extends Provider[EntityManager] {
+
+  private val emf: EntityManagerFactory = Persistence.createEntityManagerFactory("defaultPersistenceUnit")
+
+  override def get(): EntityManager = {
+    emf.createEntityManager()
+  }
+
+  def close(): Unit = {
+    if (emf.isOpen) {
+      emf.close()
+    }
+  }
+}