Add condition to show only to users with accepted sessions

app/models/ability.rb

@@ -135,6 +135,10 @@ class Ability
         event.event_ratings.peer_reviews.where(person: @user.person).any?
       end
 
+      can :buy_tickets, Conference do |conference|
+        @user.person.events.accepted_but_not_paid.where(conference_id: conference.id).any?
+      end
+
       # Submitters can either edit themselves
       can :crud, Person, id: @user.person.id
 

app/views/cfp/shared/_cfp_dashboard.html.haml

@@ -3,13 +3,14 @@
   %p=t('cfp.thanks_for_interest', :title => conference.title)
   - if cfp_hard_deadline_over?
     %p=t('cfp.hard_deadline_over')
-    %pretix-widget{:event => "https://tickets.degrowth.net/malmo2018/", :voucher => "SEBZ8X38BCDSTSYT"}
-    %noscript
-      .pretix-widget
-        .pretix-widget-info-message
-          JavaScript is disabled in your browser. To access our ticket shop without JavaScript, please
-          = succeed "." do
-            %a{:href => "https://tickets.degrowth.net/malmo2018/", :rel => "noopener", :target => "_blank"} click here
+    - if can? :buy_tickets, conference
+      %pretix-widget{:event => "https://tickets.degrowth.net/malmo2018/", :voucher => "SEBZ8X38BCDSTSYT"}
+      %noscript
+        .pretix-widget
+          .pretix-widget-info-message
+            JavaScript is disabled in your browser. To access our ticket shop without JavaScript, please
+            = succeed "." do
+              %a{:href => "https://tickets.degrowth.net/malmo2018/", :rel => "noopener", :target => "_blank"} click here
   - elsif not conference.in_the_past
     - if person.events_in(conference).size > 0
       -# if person.availabilities_in(conference).count == 0