Closes #20: contributing guidelines

Signed-off-by: Fabio José <fabiojose@gmail.com>

CONTRIBUTING.md

@@ -0,0 +1,28 @@
+# Contributing to CloudEvents' JavaScript SDK
+
+:+1::tada: First off, thanks for taking the time to contribute! :tada::+1:
+
+Following you will see some guidelines about how to contribute with
+JavaScript SDK.
+
+## Pull Requests
+
+Guidelines about how to perform pull requests.
+
+### PR to `develop`
+
+- fixes in the documentation (readme, contributors)
+- propose new files for documentation
+- implementation of new features
+
+### PR to `master`
+
+- hot fixes
+
+## Style Guide
+
+_TODO_
+
+### JavaScript Style Guide
+
+_TODO_

README.md

@@ -8,6 +8,10 @@ Official CloudEvents' SDK for JavaScript.
 
 <img src="https://github.com/cncf/artwork/blob/master/projects/cloudevents/horizontal/color/cloudevents-horizontal-color.png" width="300" height="58" alt="CloudEvents logo">
 
+## Contributing
+
+Before create an awesome PR, please read our [guidelines](./CONTRIBUTING.md).
+
 ## Versioning
 
 ### Before Spec reaches 1.0