Create CONTRIBUTING.md

Author: stan-osipov

CONTRIBUTING.md

@@ -0,0 +1,14 @@
+# Contributing
+
+Thank you for spending time and effort contributing to this repository. We do appreciate it. If you have in mind some fundamental or just big change please first discuss the change you wish to make via issue,
+email, or any other method with the owners of this repository before making a change.
+
+Please note we have a [code of conduct](https://github.com/StansAssets/com.stansassets.foundation/wiki/Code-of-Conduct), 
+and [code convention](https://github.com/StansAssets/com.stansassets.foundation/wiki/Code-Convention-Unity-C%23). Please follow it in all your interactions with the project.
+
+## Pull Request Process
+
+1. Follow the pull request template and describe what exact feature or fix you want to add and why do you think this is nessesary. 
+If feature is accepted it's describion will be included into the documentation. Please try to be as clear as possible, so we won't have to edit when updating the documentation.
+2. Increase the version numbers in the `package.json` if nessesary. The versioning scheme we use is [SemVer](http://semver.org/).
+3. Pull Request will be merged by rewier.