Add fullcalendar_view to the travis-ci build script

.travis.yml

@@ -57,7 +57,12 @@ before_script:
   - COMPOSER_MEMORY_LIMIT=-1 composer require drupal/field_inheritance
   - COMPOSER_MEMORY_LIMIT=-1 composer require drush/drush:^$DRUSH_VER
   - COMPOSER_MEMORY_LIMIT=-1 composer require mglaman/drupal-check --dev
+
+  # Because recurring_events integrates with, but does not require group and
+  # fullcalendar_view, tests fail if those modules do not exist, so here we add
+  # them manually to prevent failing tests.
   - COMPOSER_MEMORY_LIMIT=-1 composer require drupal/group:1.x-dev
+  - COMPOSER_MEMORY_LIMIT=-1 composer require fullcalendar_view
 
   - cd $DRUPAL_ROOT