[Devise Invitable]

 - Gem added.
 - Invitable fields added to User model.
[Users invitations]

 - Working ok.
[Candidate and User logins]

 - Workflow ok.
[User invitations]

 - User password saved after accept invitation.
[Candidates Invitations]

 - Candidates can be created but not invited.
 - New candidates can be invited.
 - Footer improvements.
 - Candidates and Home views improvements.
Merge branch 'invitations'
[Sendgrid Addon added]

 - Production and development environments configured.
Merge branch 'invitations'
[Home list]

 - Minor fix.
[Search bar tunned up]