fix bug in saving evaluation dates

src/Bundle/ChillPersonBundle/Resources/public/vuejs/AccompanyingCourseWorkEdit/App.vue

@@ -87,7 +87,7 @@
          <!-- list evaluations -->
          <add-evaluation
             v-for="e in pickedEvaluations"
-            v-bind:key="e.id"
+            v-bind:key="e.key"
             v-bind:evaluation="e">
          </add-evaluation>