Add hidden form element to save added exercises to collection

app/assets/javascripts/exercise_collections.js.erb

@@ -152,6 +152,7 @@ $(function() {
               '<td><a href="/exercises/' + exercise.id + '"><%= I18n.t('shared.show') %></td>' +
               '<td><a class="remove-exercise" href="#"><%= I18n.t('shared.destroy') %></td></tr>';
             exerciseList.find('tbody').append(template);
+            $('#exercise-list').find('option[value="' + exercise.id + '"]').prop('selected', true);
           }
         }
       });

app/views/exercise_collections/_form.html.slim

@@ -29,6 +29,8 @@
             td
               a.remove-exercise href='#' = t('shared.destroy')
     button.btn.btn-primary type='button' data-toggle='modal' data-target='#add-exercise-modal' = t('exercise_collections.form.add_exercises')
+    .hidden
+      = f.collection_select(:exercise_ids, Exercise.all, :id, :title, {}, {class: 'form-control', multiple: true})
 
   .actions = render('shared/submit_button', f: f, object: @exercise_collection)