fetch postParticipation request, catch fetch error, store mutation+action

src/Bundle/ChillPersonBundle/Resources/views/AccompanyingCourse/show.html.twig

@@ -5,15 +5,13 @@
 {% endblock %}
 
 {% block content %}
-
    <h1>{{ block('title') }}</h1>
-   
    <div id="accompanying-course"></div>    
+{% endblock %}
 
-   {{ encore_entry_script_tags('accompanying_course') }}
-
+{% block js %}
    <script type="text/javascript">
       window.accompanyingCourseId = {{ accompanyingCourse.id|e('js') }};
    </script>
-   
+   {{ encore_entry_script_tags('accompanying_course') }}
 {% endblock %}