added model NewsletterOrders and migration
contact form html partial
added create_newsletter view and method
removed deprecated stuff in PR-Language model
added stuff
Merge branch 'master' into feature/newsletter2.0

Conflicts:
	db/schema.rb
fixed stuff
Merge branch 'master' into add_contact_address
adapt page layout for contact snippet
created views for mail and newsletter controller
moved method from student to newsletter order
added model validations
completed create_newsletter_view
Merge remote-tracking branch 'origin/master' into feature/newsletter2.0
fixed check_for_expired method
adapted to empty search_params
moved to new css file
moved stuff from students_controller to newsletter
updated newsletter views
created cron job and introduced letter_opener gem