I have two applications, appA and appB. I want to use single sign on
for both the apps.
Meaning, if a user logs in to appA, he dont have to login to appB and
conversely, if a user logged out of appA, it logs him out of appB too.
Just like in google's various products.

I created the sessions table in appA. How do i access the sessions
table in appB.
I tried to put ActiveRecord::Base.establish_connection :appA in the
config\initializers\session_store.rb of appB,
but that connects the whole appB application to appA database. I only
want to access the sessions table.

How do i do it?

database.yml of appB has:
appA:
 adapter: mysql
 database: appa_dev
 pool: 5
 username: app_user
 password: app_pwd
 host: localhost