add findRunningGamesOfUser to ServerApp

fh.fd.ci.server/src/main/java/de/fd/fh/ServerApp.java

@@ -58,6 +58,7 @@ public class ServerApp
 
         post("/games", gameController::createGame);
         get("/games/:game_id", gameController::findGameById);
+        get("/games/findByUser/:user_id", gameController::findRunningGamesOfUser);
 
         get("/hello", (req, res) -> "Hello World");