Merge pull request #474 from Unity-Technologies/docs/contrib-guidelines-fix

Moved contrib guidelines to be recognized by Github

README.md

 ## Documentation and References
 
 **For more information, in addition to installation and usage
-instructions, see our [documentation home](docs/README.md).** If you have
+instructions, see our [documentation home](docs/Readme.md).** If you have
 used a version of ML-Agents prior to v0.3, we strongly recommend 
 our [guide on migrating to v0.3](docs/Migrating-v0.3.md).
 
 
 ML-Agents is an open-source project and we encourage and welcome contributions.
 If you wish to contribute, be sure to review our 
-[contribution guidelines](docs/Contribution-Guidelines.md) and 
+[contribution guidelines](CONTRIBUTING.md) and 
 [code of conduct](CODE_OF_CONDUCT.md).
 
 You can connect with us and the broader community

docs/Learning-Environment-Examples.md

 page.
 
 If you would like to contribute environments, please see our 
-[contribution guidelines](Contribution-Guidelines.md) page. 
+[contribution guidelines](CONTRIBUTING.md) page. 
 
 ## Basic