GREG-4: Simple admin interface

Adding simple admin interface.

Also added a class that can be used to add data to a test database. Can be useful for getting some dummy data into the database when developing.

approved this merge request

added 2 commits

• 1ead0633 - Not allowing blank for optional date, use null instead
• 10d18b6d - GREG-4: Adding more customizations to admin site

Compare with previous version

marked this merge request as ready

requested review from @andretol

changed the description

Recent changes look good. Not sure what magic I should do in Gitlab to approve again.

merged

mentioned in commit d512e792