redirect to subject details after adding a subject - #86

Closes #86 (closed)

no impact on database

this makes use of the django messages feature: https://docs.djangoproject.com/en/1.10/ref/contrib/messages/

to create a message that will appear on the next page accessed:

from django.contrib import messages
messages.add_message(request, messages.SUCCESS, 'Hello world.')

it's also possible to use messages.ERROR but the templates will have to be adapted to map it to the proper alert class (i.e. danger). See https://almsaeedstudio.com/themes/AdminLTE/pages/UI/general.html (Alerts and callouts).

merged

mentioned in commit be6747df