commit eb82f272f0c442a83cf2ea8d140105a64fb41b3b
author Yegor <yjbanov@google.com> Tue Oct 10 10:02:21 2017 -0700
committer GitHub <noreply@github.com> Tue Oct 10 10:02:21 2017 -0700
tree 9561bd0e5ddd0aefadf8db905fd7289e4cc7e307
parent 74e58f66d492a28a2c47ac5402d0b8b8a740cf62

CONTRIBUTING.md: suggest skipping intro (#4188)

...if the environment is already setup

CONTRIBUTING.md

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index d0c7030..e8f5c8a 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -3,6 +3,17 @@
 
 [![Build Status](https://travis-ci.org/flutter/engine.svg)](https://travis-ci.org/flutter/engine)
 
+I built it before. Remind me, how do I do it again?
+--------------------
+
+If you have previously built the engine (i.e. your environment is already setup) and just want a refresher, then feel free to skip to one of the following sections:
+
+- [Build for Android](#android-cross-compiling-from-mac-or-linux)
+- [Build for iOS](#ios-cross-compiling-from-mac)
+- [Build flutter_tester](#desktop-mac-and-linux-for-tests)
+
+Otherwise, begin from the next section, which will help you prepare your environment.
+
 Things you will need
 --------------------