Update README.md

Author: yunxing

README.md

@@ -9,6 +9,8 @@
 
 Example project using Reason as an `yarn` dependency.
 
+(For instructions using npm, see [Reason via npm](https://github.com/reasonml/ExampleProject/blob/master/README-NPM.md))
+
 ## Install yarn:
 
 yarn is a fast, reliable, and secure dependency management tool. You can now use yarn to install reason.
@@ -34,31 +36,7 @@ The top level `rtop` is built in to the sandbox:
 ```sh
 # Opens `rtop` from the sandbox.
 yarn top
-```
-
-# Reason via `npm`
-
-Example project using Reason as an `npm` dependency.
-
-## Get Started:
 
-```sh
-git clone https://github.com/reasonml/ExampleProject.git
-cd ExampleProject
-npm install
-npm start
-```
-
-If you are running as `root` already (you probably aren't) then invoke `npm
-install --unsafe-perm` instead.
-
-## Included Top Level
-
-The top level `rtop` is built in to the sandbox: 
-
-```sh
-# Opens `rtop` from the sandbox.
-npm run top
 ```
 
 # Editor Support