copy changes for registration and ethos emails
add utm tracking to all emails
Turn string literal into interpolated string

For strings with interpolation in them (`#{...}`) you need to have double quotes `"` instead of `'`
change host change email copy
Merge branch 'email-copy' of https://github.com/TeaWithStrangers/tws-on-rails into email-copy
fix subject variable for tt confirmation
fix merge
Update flake.markerb

Fix `url_for` line wrapping.
Update host_changed.markerb

Remove whitespace
correct some utm sources, spacing, parameters
redo follow up email to attendees
quick change
Update all mail calls to send both formats. Closes #214
Merge remote-tracking branch 'origin/mail-format' into email-copy-tests

Fixes #214

Conflicts:
	app/mailers/attendance_mailer.rb
	app/mailers/tea_time_mailer.rb
	app/mailers/user_mailer.rb
Add test for registration mailer
Minimal Attendance Mailer specs+some bugfixes
I did just say we were testing rendering...
Fix attendance mailer
User Mailer spec and fixes
Update Sendgrid Category for every mail