Make 'Next shifts' columns multi-line

shiftregister/team/templates/shift_overview.html

@@ -13,7 +13,7 @@
 <hr>
 {% endif %}
 <h3 class="title is-spaced">Nächste Schichten pro Raum</h3>
-<div class="columns">
+<div class="columns is-multiline">
 {% for shift in next_shifts %}
     <div class="column is-one-quarter">
         <h5 class="subtitle">{{ shift.room.name }}</h5>