One thing that I wanted to form validation within oa-identity and that I would not be forwarded to an error page on invalid authentication. Therefore, I modified oa-identity to do some simple form validation. It's not pretty but it's functional.
I have built upon my previous tutorial and have added a username as my authentication key rather than email - which is the default authentication key.
I start my journey into Ruby on Rails learning how to use OA-Identity with OmniAuth, currently in the 1.0-beta branch. The learning curve was quite high for me but I finally nailed it!