Add coaches as organisers on an event
Added phone number to coaches
require phone number for organisers
fix specs 
not sure how to test validation on coach object
Merge pull request #147 from railsgirlslondon/add_coaches_as_organizer

Add coaches as organizer
Merge branch 'master' of github.com:railsgirlslondon/railsgirls-london
add yammer logo
Remove requirement for Ruby 2.0.0-p195
Remove dotted link indicator for sponsors
user correct syntax