Provide demo data as Untis dump

fixtures/README.rst

+Example data for AlekSIS-App-Untis
+==================================
+
+In this directory, you can find MySQL dumps from Untis Multiuser databases
+with some anonymised demo data. You can restore them in your local MySQL
+database to test and develop the import procedure. Please pay attention that
+the data are partially stripped – all license data, for example, are just
+faked.
+
+If you just want to work with timetable data, you may use the demo data 
+already extracted to Django models provided in AlekSIS-App-Chronos.
+
+It could be pretty annoying to work with demo data with dates that are
+only in the past. This makes it nearly impossible to test views and
+functions that should show something for the current date, for example.
+The management command ``move_dates_for_testing`` move all Chronos and school term
+dates of the latest school term in the database as it would currently
+take place:
+
+::
+
+    aleksis-admin move_dates_for_testing
+
+If you want to test the command without directly changing your data,
+you could also do a dry run:
+
+::
+
+    aleksis-admin move_dates_for_testing --dry