create group is a button now

templates/group/list_groups.twig

@@ -2,9 +2,11 @@
 {% block content %}
     <div style="grid-column:1/2; grid-row:1/2">
         <h1> List groups </h1>
-        <a href="/groups/create">Create a group</a>
+        <form action="/groups/create">
+            <button type="submit" class="ui button">Create a group</button>
+        </form>
     </div>
-    <div class="ui relaxed divided list" id="list">
+    <div class="ui relaxed divided list" id="list" style="max-height:590px;">
     {% for group in groups %}
         <a href="groups/{{group.id}}" class="item">
             <div class="ui horizontal label">