From e3d5a7d646256a2609e5e429c68118c30d64450a Mon Sep 17 00:00:00 2001
From: Daniel Tschinder <daniel@tschinder.de>
Date: Mon, 5 Sep 2016 23:31:46 +0200
Subject: [PATCH] Update contributing [skip ci] (#108)

* Update contributing [skip ci]

* typo
---
 CONTRIBUTING.md | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index fc491e86a8..6188ba550a 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -3,3 +3,42 @@
 Contributions are always welcome, no matter how large or small. Before
 contributing, please read the
 [code of conduct](https://github.com/babel/babel/blob/master/CODE_OF_CONDUCT.md).
+
+## Setup local env
+
+To start developing on babylon you only need to install its dependencies:
+
+```bash
+npm install
+```
+
+After this step you can now start and run the tests:
+
+```bash
+npm test
+```
+
+## Cross repository changes
+
+If you are making changes to babylon which make it necessary to also change things in babel you will want to link both repositories together. This can be done by doing the following (assuming you have both babel and babylon already checked out):
+
+```bash
+cd babylon/
+npm link
+npm run build
+cd ../babel/
+make bootstrap
+npm link babylon
+cd packages/babel-core/
+npm link babylon
+cd ../../packages/babel-template/
+npm link babylon
+cd ../../packages/babel-traverse/
+npm link babylon
+cd ../../packages/babel-generator/
+npm link babylon
+make build
+make test
+```
+
+From now on babel will use your local checkout of babylon for its tests.