use truncate table instead
reset primary key seq for all tables when seeding
delte all broadcast formats at the start of the script
split seeds.rb

into a seeds.rb and a event_types_seeds.rb
the 2nd is included in the spec helper, because the Event model required EventTypes to be present
also delete data from table in sqlite
Merge branch 'master' into fix-primary-key-reset
Merge pull request #191 from koelncampus/fix-primary-key-reset

this should fix failing test due to invalid ids of supposedly reset primary keys