Add ColPrac guide

Author: devmotion

README.md

@@ -1,6 +1,22 @@
-# DynamicPPL
+# DynamicPPL.jl
 
 [![Build Status](https://travis-ci.com/TuringLang/DynamicPPL.jl.svg?branch=master)](https://travis-ci.com/TuringLang/DynamicPPL.jl)
 [![Codecov](https://codecov.io/gh/TuringLang/DynamicPPL.jl/branch/master/graph/badge.svg)](https://codecov.io/gh/TuringLang/DynamicPPL.jl)
+[![ColPrac: Contributor's Guide on Collaborative Practices for Community Packages](https://img.shields.io/badge/ColPrac-Contributor's%20Guide-blueviolet)](https://github.com/SciML/ColPrac)
 
 A domain-specific language and backend for probabilistic programming languages, used by [Turing.jl](https://github.com/TuringLang/Turing.jl).
+
+## Do you want to contribute?
+
+If you feel you have some relevant skills and are interested in contributing then please do get in touch and open an issue on Github.
+
+This project follows the [ColPrac guide on collaborative practices](http://colprac.sciml.ai/), apart from the following slight variation:
+
+- The master branch contains the most recent release at any point in time. All non-breaking changes (bug fixes etc.) are merged directly into master and a new patch version is released immediately.
+- A separate dev branch contains all breaking changes, and is merged into master when a minor version release happens.
+
+For instance, suppose we are currently on version 0.13.5.
+
+- If someone produces a bug fix, it is merged directly into master and bumps the version to 0.13.6. This change is also merged into dev so that it remains up-to-date with master.
+- If someone is working on a new feature that is not breaking (performance-related, fancy new syntax that is backwards-compatible etc.), the same happens.
+- New breaking changes are merged into dev until a release is ready to go, at which point dev is merged into master and version 0.14 is released.