Update README.md

Author: AimalAzmi

README.md

@@ -32,7 +32,7 @@ and you should have a help section that explains everything quite briefly on how
 
 ## Contributing
 
-Please read [CONTRIBUTING.md](https://gist.github.com/PurpleBooth/b24679402957c63ec426) for details on our code of conduct, and the process for submitting pull requests to us.
+Please read [CONTRIBUTING.md](https://github.com/AimalAzmi/codeigniter-migrations/blob/master/CONTRIBUTING.md) for details on our code of conduct, and the process for submitting pull requests to us.
 
 ## Authors