Update Docker install direction to mention non-root

Change-Id: I57b8e48d30630b9f00e4165d7ae2622faa264db4
diff --git a/GettingStarted.md b/GettingStarted.md
index 94cd2f6..b8200f0 100644
--- a/GettingStarted.md
+++ b/GettingStarted.md
@@ -37,6 +37,7 @@
 ## Build the tree
 
 To isolate the build from your host system, we build using Docker.
+We recommend configuring Docker so that a non-root user can use it.
 For gLinux users, follow the [install instructions here](http://go/installdocker).
 
 For all other users, follow the [official directions](https://docs.docker.com/install)