Update template 'jwinf': Fix link to challenges

templates/jwinf/index.hbs

@@ -14,7 +14,7 @@
 
       <div class="columns">
         <div class="column is-4 is-offset-2">
-          <a href="/contest/open/">
+          <a href="/contest/?filter=open">
             <div class="notification" style="background-color:#e5fae5">
               <h3 class="title is-4">Trainingsaufgaben</h3>
               <h4 class="subtitle is-5">Zum Ausprobieren und Üben</h4>
@@ -24,7 +24,7 @@
           </a>
         </div>
         <div class="column is-4 is-offset-0">
-          <a href="/contest/current/">
+          <a href="/contest/?filter=current">
             <div class="notification" style="background-color:#e5f0f8">
               <h3 class="title is-4">Jugendwettbewerb Informatik</h3>
               <h4 class="subtitle is-5">Aktuelle Wettbewerbe</h4>
@@ -36,7 +36,7 @@
       </div>
       <div class="columns">
         <div class="column is-4 is-offset-2">
-          <a href="/contests/special/">
+          <a href="/contest/?filter=challenge">
             <div class="notification" style="background-color: #d2222217">
               <h3 class="title is-4">Herausforderungen</h3>
               <img src="/static/images/gross.png" style="width:50%; margin: 0px 25% 25px;">