feat(websocket)!: Implement WebSocket connection and event handling

knockoutwhistweb/app/logic/user/UserManager.scala

@@ -8,9 +8,13 @@ import model.users.User
 trait UserManager {
 
   def addUser(name: String, password: String): Boolean
+
   def authenticate(name: String, password: String): Option[User]
+
   def userExists(name: String): Option[User]
+
   def userExistsById(id: Long): Option[User]
+
   def removeUser(name: String): Boolean
 
 }