Added instructions for using Metaforce with OAuth in Rails

[martyychang]

I verified that this approach works in my Rails app

[LucasCioffi]

@martyychang do you remember if this gem uses a refresh token if the auth token has expired? I didn't see the refresh token mentioned in this PR.

I see that the Restforce gem does use a refresh token here:

The middleware will use the refresh_token automatically to acquire a new access_token if the existing access_token is invalid.

Thank you!

[martyychang]

Hi @LucasCioffi I apologize but it's been a long time since I'd looked at this app or touched Ruby. :( I'm interpreting the pr—which may as well have been created by another developer at this point—as more of a workaround or quick hack for a developer to get some connectivity going.

Otherwise perhaps it's possible that the omniauth-salesforce gem is handling authentication and the refresh token, with the access token being what gets passed to the Metaforce object as needed.

[LucasCioffi]

@martyychang Thanks for the insight!