Replace Pledgie with Gittip [ci skip]

CONTRIBUTING.md

@@ -14,10 +14,10 @@ improve this project. Here are some ways *you* can contribute:
 * Refactor code.
 * Fix [issues][].
 * Review patches.
-* Financially pledge using [Pledgie][].
+* Financially pledge using [gittip][].
 
 [issues]: https://github.com/sferik/twitter/issues
-[Pledgie]: http://pledgie.com/campaigns/18388
+[gittip]: https://www.gittip.com/sferik/
 
 ## Submitting an Issue
 We use the [GitHub issue tracker][issues] to track bugs and features. Before

README.md

@@ -5,14 +5,14 @@
 [![Dependency Status](https://gemnasium.com/sferik/twitter.png?travis)][gemnasium]
 [![Code Climate](https://codeclimate.com/github/sferik/twitter.png)][codeclimate]
 [![Coverage Status](https://coveralls.io/repos/sferik/twitter/badge.png?branch=master)][coveralls]
-[![Click here to make a donation](http://www.pledgie.com/campaigns/18388.png)][pledgie]
+[![Gittip](http://img.shields.io/gittip/sferik.png)][gittip]
 
 [gem]: https://rubygems.org/gems/twitter
 [travis]: http://travis-ci.org/sferik/twitter
 [gemnasium]: https://gemnasium.com/sferik/twitter
 [codeclimate]: https://codeclimate.com/github/sferik/twitter
 [coveralls]: https://coveralls.io/r/sferik/twitter
-[pledgie]: http://pledgie.com/campaigns/18388
+[gittip]: https://www.gittip.com/sferik/
 
 A Ruby interface to the Twitter API.
 
@@ -137,7 +137,7 @@ end
 
 ```ruby
 client.user do |message|
-  puts message 
+  puts message
 end
 ```