feat(itim): Add ticket tab to clusters

shows related tickets

ref: #296 #309

app/itim/views/clusters.py

@@ -4,6 +4,7 @@ from django.utils.decorators import method_decorator
 
 from core.forms.comment import AddNoteForm
 from core.models.notes import Notes
+from core.models.ticket.ticket_linked_items import Ticket, TicketLinkedItem
 from core.views.common import AddView, ChangeView, DeleteView, IndexView
 
 from itim.forms.clusters import ClusterForm, DetailForm
@@ -152,6 +153,11 @@ class View(ChangeView):
 
         context = super().get_context_data(**kwargs)
 
+        context['tickets'] = TicketLinkedItem.objects.filter(
+            item = int(self.kwargs['pk']),
+            item_type = TicketLinkedItem.Modules.CLUSTER
+        )
+
         context['notes_form'] = AddNoteForm(prefix='note')
         context['notes'] = Notes.objects.filter(service=self.kwargs['pk'])