Make contributing/CoC links absolute

Author: christopheradams

README.md

@@ -1097,8 +1097,8 @@ best practices in Elixir.
 Feel free to open tickets or send pull requests with improvements.
 Thanks in advance for your help!
 
-Check the [contributing guidelines](CONTRIBUTING.md)
-and [code of conduct](CODE_OF_CONDUCT.md) for more information.
+Check the [contributing guidelines][Contributing]
+and [code of conduct][Code Of Conduct] for more information.
 
 ### Spread the Word
 
@@ -1127,6 +1127,8 @@ project.
 <!-- Links -->
 [Chinese Traditional]: https://github.com/elixirtw/elixir_style_guide/blob/master/README_zhTW.md
 [Code Analysis]: https://github.com/h4cc/awesome-elixir#code-analysis
+[Code Of Conduct]: https://github.com/christopheradams/elixir_style_guide/blob/master/CODE_OF_CONDUCT.md
+[Contributing]: https://github.com/christopheradams/elixir_style_guide/blob/master/CONTRIBUTING.md
 [Contributors]: https://github.com/christopheradams/elixir_style_guide/graphs/contributors
 [Elixir Style Guide]: https://github.com/christopheradams/elixir_style_guide
 [Elixir]: http://elixir-lang.org