added sponsors

Author: ryanflorence

README.md

@@ -141,8 +141,13 @@ render((
 
 See more in the [Introduction](/docs/Introduction.md), [Advanced Usage](/docs/guides/advanced/README.md), and [Examples](/examples).
 
+
+
 ### Thanks
 
+Thanks to [our sponsors](/SPONSORS.md) for supporting the development of
+React Router.
+
 React Router was initially inspired by Ember's fantastic router. Many thanks to the Ember team.
 
 Also, thanks to [BrowserStack](https://www.browserstack.com/) for providing the infrastructure that allows us to run our build in real browsers.

SPONSORS.md

@@ -0,0 +1,7 @@
+The following companies have provided sponsorship toward the development
+of React Router. Thank you!
+
+- [React Training](https://reactjs-training.com)
+- [![Modus Create](http://i.imgur.com/FxzUtvl.png)](http://moduscreate.com/)
+- [![Instructure](http://i.imgur.com/kMZauLm.png)](https://www.instructure.com/)
+