add API to spend Gittip balance elsewhere

[chadwhitacre]

From @tonylampada on #214:

This is what the user experience, using FS:

1. FS user "tonylampada" makes a U$ 10 offer for a new open source project, like this one --> http://www.freedomsponsors.org/core/issue/13/a-complete-jee-sample-application-using-maven-hibernate-jpa-and-google-guice
2. FS user "javamaster" creates a github project that addresses the issue
3. "tonylampada" is very happy with the solution and wants to pay, but he doesn't like paypal. He's already has some balance on gittip, and he'd like to use that.
4. "tonylampada" connects his gitbuh account to his FS account.
5. "javamaster" also has a connected github account
6. "tonylampada" selects "pay offer with Gittip"
7. "tonylampada" is redirected to "gittip direct pay" page, that says
   Payment confirmation
   -- "javamaster" ....... 9.70
   -- "freedomsponsors" .... 0.30
   Confirm? (Y/n)
8. "tonylampada" clicks yes
9. U$ 10 is taken from "tonylampada" gittip account, (using the same rules that already apply every friday).
10. "tonylampada" is redirected to FS page that says:
    "Payment OK"

Something like that.
The implementation on Gittip side would actually be completely decoupled from FS.
Have you ever thought of enabling Gittip to be used as payment gateway like above?

[thiloplanz]

+1 for this. But this should be limited to vetted partners that do things along the lines of gittip's mission, such as FS or Flattr (#284), not just anything. We don't want to become a general purpose payment processor with all the pain that involves. In the case of Flattr, I guess this could also go both ways (withdrawing Flattr revenues into a gittip balance).

[chadwhitacre]

I'm closing this as out of scope for where we are right now (cf. #827).