Merge tag 'v1.21' into develop

fix - compare chart now checks if id exists

rowers/views.py

@@ -3274,6 +3274,9 @@ def workout_comparison_view2(request,id1=0,id2=0,xparam='distance',
 	result = request.user.is_authenticated() and ispromember(request.user)
 	if result:
 	    promember=1
+
+    if not Workout.objects.filter(id=id1).exists() or not Workout.objects.filter(id=id2).exists():
+        raise Http404("Workout doesn't exist")
         
     # create interactive plot
     res = interactive_comparison_chart(id1,id2,xparam=xparam,yparam=yparam,