Fix mostly postgres-specific troubles caused by Rails 4 migration

* Avoid deadly "group" + "find_each" combo by making the
  user's page just fetch everything outright without find_each
* Add 'event' to the group clause for a query that wanted it to be there
* Remove reference to attr_accessible from a migration
  so it will actually work if someone runs the migrations fresh
Fix rake db:seed for Rails 4

Apparently update_attributes with incorrect attrs used to succeed
quietly, whereas now it raises an exception. So maybe the solution
is to not send incorrect stuff.
Rspec 3.0! Welcome to THE FUTURE

Still using 'should' syntax for now. Maybe I'm not ready for the future?
wip