Use bootstrap grid for lesson card.

biscuit/apps/chronos/templates/chronos/tt_lesson.html

 <div class="card" style="width: 18rem; {% if lesson.colour_fg %} color: {{ lesson.colour_fg }}; {% endif %} {% if lesson.colour_bg %} background-color: {{ lesson.colour_bg }}; {% endif %}">
-  <div class="card-body">
-    <h5 class="card-title">{{ lesson.subject.abbrev }}</h5>
-    <h6 class="card-text">Rooms {# Will be implemented soon#}</h6>
-    <ul>
-     <li>!lesson.teachers{{ lesson.teachers }}</li>
-     <li>!lesson.groups{{ lesson.groups }}</li>
-    </ul>
-    <a href="#" class="card-link">Room informations</a>
+ <div class="card-body">
+  <div class="row">
+   <div class="col-sm">
+    <span class="card-title">{{ lesson.subject.abbrev }}</span>
+   </div>
   </div>
+  <div class="row">
+   <div class="col-sm">
+    {% for group in lesosn.groups %}
+     <span class="card-text">{{ group.short_name }}</span>
+    {% endfor %}
+   </div>
+   <div class="col-sm">
+    {% for teacher in lesosn.teachers %}
+     <span class="card-text">{{ teacher.short_name }}</span>
+    {% endfor %}
+   </div>
+   <div class="col-sm">
+    {# FIXME really add room information #}
+    <span class="card-text">Room</span>
+   </div>
+  </div>
+ </div>
 </div>