implement redirect after login

public/static/js/maps.js

@@ -69,7 +69,7 @@
         printTimeForHuman: function (time) {
             const minutes = Math.floor(time / 60);
             const seconds = time % 60;
-            var time_str = ''; 
+            var time_str = '';
 
             if (minutes == 1) {
                 time_str += '1 minute';
@@ -141,9 +141,7 @@
     if (document.getElementById('challengeButton')) {
         document.getElementById('challengeButton').onclick = function () {
             MapGuesser.showModal('challenge');
-            document.getElementById('createNewChallengeButton').href = '/challenge/new/' + this.dataset.mapId;
             document.getElementById('playMode').style.visibility = 'hidden';
-            
             var timeLimit = document.getElementById('timeLimit').value;
             document.getElementById('timeLimitLabel').innerText = 'Time limit of ' + Util.printTimeForHuman(timeLimit);
         };