Expiration for signed global ids.

Adds #27.

At the moment this is for some discussion with some code.

I've taken the approach of only storing `expires_at` and converting from that when accessing `expires_in`.

I have some trouble condensing just how `expires_in`  and `expires_at` work together, and on top of that, they should work on both the instance and class level... :grin:

For instance with this set up turning off `expires_in` (by passing `nil`) at the instance level wouldn't work, because it would use the class level `expires_in`.

Basically I just want to know if I'm headed somewhere :smile:
Actually let me push what I have now. I still need tests and it hasn't been rebased yet.

Den 22/08/2014 kl. 14.37 skrev Tony Han <notifications@github.com>:

> In lib/global_id/signed_global_id.rb:
> 
> > @@ -21,23 +21,48 @@ def pick_verifier(options)
> >        end
> >      end
> >  
> > +    def expires_in
> > +      expires_at ? Time.now - expires_at : Time.now
> OK
> 
> —
> Reply to this email directly or view it on GitHub.
> 

--
Kasper