Fix missing / at end of url

Fixes #2

app/src/main/java/fr/mobdev/lpcprog/dialog/ServerDialog.java

@@ -67,6 +67,10 @@ public class ServerDialog extends DialogFragment {
                         EditText urlText = (EditText) view.findViewById(R.id.url_text);
                         if(urlText.getText().length() > 0)
                             url += urlText.getText();
+                        else
+                            return;
+                        if(!url.endsWith("/"))
+                            url += "/";
                         //add server to database
                         DatabaseManager.getInstance(getActivity().getApplicationContext()).addServer(url);
                         listener.updateServerList();