Merge branch 'fix/order-admin' into 'develop'

Add participant order field to the Event admin

See merge request hub/hub!1094

src/core/admin.py

@@ -603,7 +603,7 @@ class EventAttachmentInline(admin.TabularInline):
 
 class EventParticipantInline(admin.TabularInline):
     model = EventParticipant
-    fields = ['participant', 'role', 'is_accepted', 'is_public']
+    fields = ['participant', 'role', 'is_accepted', 'is_public', 'order']
     extra = 1
     raw_id_fields = ['participant']