From the sound of it you'll need to install the ruby-openid gem and enable OpenID support that's already in Redmine. It's optional and by default is turned off. To turn it on, go to the Administration panel > Authentication and select the OpenID checkbox. When enabled this will allow users to login through their OpenID url.
Successfully installed ruby-openid-2.1.7
but no one OpenId checkboxes in Administration panel > Authentication.
What I miss?