[in the wild] add Mighty Spring

Author: hshoff

README.md

@@ -1463,6 +1463,7 @@
   - **GoodData**: [gooddata/gdc-js-style](https://github.com/gooddata/gdc-js-style)
   - **Grooveshark**: [grooveshark/javascript](https://github.com/grooveshark/javascript)
   - **How About We**: [howaboutwe/javascript](https://github.com/howaboutwe/javascript)
+  - **Mighty Spring**: [mightyspring/javascript](https://github.com/mightyspring/javascript)
   - **MinnPost**: [MinnPost/javascript](https://github.com/MinnPost/javascript)
   - **ModCloth**: [modcloth/javascript](https://github.com/modcloth/javascript)
   - **National Geographic**: [natgeo/javascript](https://github.com/natgeo/javascript)