Devise restrict concurrent login


I am using devise 1.0.8, and I want to restrict concurrent login of user
i.e. same user should not be login from different browser or different
location if he already login from some where.

and if he really wants to login forcefully then other side sessions for
that user should be clear and he should be logout from other sides.

Any help would be greatly appreciated.

Clearance does this:

In principle you should be able to do the same thing in Devise (reset
the authentication token on each signin).

--Matt Jones