Add live dashboard for teachers in the context of an exercise

This commit also adds the fundamentals for ActionCable

app/views/exercises/study_group_dashboard.html.slim

@@ -0,0 +1,21 @@
+h1
+  = t('.live_dashboard')
+
+div.teacher_dashboard data-exercise-id="#{@exercise.id}" data-study-group-id="#{@study_group_id}"
+
+h4
+  = t('.related_requests_for_comments')
+
+.table-responsive
+  table.table.table-hover.mt-4
+    thead
+      tr
+        th.text-center
+          i.mr-0 class="fa fa-lightbulb-o" aria-hidden="true" title = t('request_for_comments.solved')
+        th.text-center
+          i.mr-0 class="fa fa-comment" aria-hidden="true" title = t('request_for_comments.comments') align="center"
+        th.col-12 = t('activerecord.attributes.request_for_comments.question')
+        th = t('activerecord.attributes.request_for_comments.username')
+        th.text-nowrap = t('activerecord.attributes.request_for_comments.requested_at')
+      tbody#posted_rfcs
+        = render(partial: 'request_for_comments/list_entry', collection: @request_for_comments, as: :request_for_comment)

app/views/layouts/application.html.slim

@@ -5,6 +5,7 @@ html lang='en'
     meta name='viewport' content='width=device-width, initial-scale=1'
     title = application_name
     link href=asset_path('favicon.png') rel='icon' type='image/png'
+    = action_cable_meta_tag
     = stylesheet_pack_tag('application', media: 'all', 'data-turbolinks-track': true)
     = stylesheet_pack_tag('stylesheets', media: 'all', 'data-turbolinks-track': true)
     = stylesheet_link_tag('application', media: 'all', 'data-turbolinks-track': true)
@@ -12,6 +13,7 @@ html lang='en'
     = javascript_include_tag('application', 'data-turbolinks-track': true)
     = yield(:head)
     = csrf_meta_tags
+    = timeago_script_tag
   body
     - unless @embed_options[:hide_navbar]
       nav.navbar.navbar-dark.bg-dark.navbar-expand-md.mb-4.py-1 role='navigation'

app/views/request_for_comments/_list_entry.html.slim

@@ -0,0 +1,15 @@
+tr.table-row-clickable data-id=request_for_comment.id data-href=request_for_comment_path(request_for_comment)
+  td.p-2
+    - if request_for_comment.solved?
+      span.fa.fa-check.fa-2x.text-success aria-hidden="true"
+    - elsif request_for_comment.full_score_reached
+      span.fa.fa-check.fa-2x style="color:darkgrey" aria-hidden="true"
+    - else
+      = ''
+  td.text-center = request_for_comment.comments_count
+  - if request_for_comment.has_attribute?(:question) && request_for_comment.question.present?
+    td.text-primary = truncate(request_for_comment.question, length: 200)
+  - else
+    td.text-black-50.font-italic = t('request_for_comments.no_question')
+  td = request_for_comment.user
+  td = timeago_tag request_for_comment.created_at