app/views/devise/mailer/_customer.html.haml
%p= "Hello #{resource.name} <#{resource.email}>,"
%p
#{resource.company.owner.name} has invited you to #{link_to 'EasyKeep', root_url}, to view your account history.
You can accept this invitation through the link below.
%p= link_to 'Accept invitation', accept_invitation_url(resource, :invitation_token => @token)
%p
If you don't want to accept the invitation, please ignore this email.
%br/
Your account won't be created until you access the link above and set your password.