implemented missing returns.

src/main/java/de/hs_mannheim/facade/Application.java

@@ -13,19 +13,21 @@ public class Application {
     }
 
     public boolean sign_in_user(String username, String password){
-        return true;
+        return running_system.sign_in_user(username, password);
     }
 
     public boolean sign_up_user(String username, String password, String hometown, String zip,
                                 String car_name, String car_co2_km, String car_avg_kmh, String bike_avg_kmh){
-        return true;
+        return running_system.sign_up_user(username, password, hometown, zip, car_name, car_co2_km, car_avg_kmh, bike_avg_kmh);
     }
 
-    public void sign_out_user(){}
+    public void sign_out_user(){
+        running_system.sign_out_user();
+    }
 
     public boolean change_user_details(String username, String password, String hometown, String zip,
                                 String car_name, String car_co2_km, String car_avg_kmh, String bike_avg_kmh){
-        return true;
+        return running_system.change_user_details(username, password, hometown, zip, car_name, car_co2_km, car_avg_kmh, bike_avg_kmh);
     }
 
     public ArrayList<String> search(String hometown_or_zip){
@@ -49,10 +51,12 @@ public class Application {
     }
 
     public String[] getDetails(){
-        return System.getDetails();
+        return running_system.getDetails();
     }
 
-    public String distnace(String zip){
+    public String distance(String zip){
         return running_system.distance(zip);
     }
+
+
 }