add role to UserCompany, remove schema.rb
add `index` and `update` action to api/users
add angular users controller, service, tests, route and template
fix project <-> identity association
fix tests for `Invite` model
add route, invites_controller and controller tests
add angular service, controller, route, template, tests for invite form
add mailer for sending invites
fixed invites

* move filter authorize_admin to application controller
* create method Invite.mass_create and using it in invites controller
* rename method UserMailer#invite_email to #invite
* fixed User#role and User#admin? methods
* add parameter role to method User#add_to_company
* remove constants from UserCompany
* remove UserCompany#assgin_default_role
* fixed migration add_role_to_user_companies
* fixed specs
* create method Company#default_user_role and using it in invites and
  signup
* using company_id instead company_name in invites
* update /ui/users
Merge pull request #24 from vexor/user_invites

User invites