Update local install instructions and add add more verbose instructio…

…ns when node versions don't match (#7847)

Updates the contributing README to clarify install instructions for a local environment and what the successful script looks like. Suggests updates to the setup script to provide more instructions if nvm install fails in the bash script.

CONTRIBUTING.md

@@ -22,11 +22,44 @@ To test the plugin, or to contribute to it, you can clone this repository and bu
 
 ### Local Environment
 
-First, you need a WordPress Environment to run the plugin on. The quickest way to get up and running is to use the provided docker setup. Just install [docker](https://www.docker.com/) and [docker-compose](https://docs.docker.com/compose/) on your machine and run `./bin/setup-local-env.sh`.
+First, you need a WordPress Environment to run the plugin on. The quickest way to get up and running is to use the provided docker setup. Install [docker](https://www.docker.com/) and [docker-compose](https://docs.docker.com/compose/) by following the most recent instructions on the docker site.
+
+In the folder of your preference, clone this project and enter the working directory:
+```bash
+git clone git@github.com:WordPress/gutenberg.git
+cd gutenberg 
+```
+
+Then, run a setup script to check if docker and node are configured properly and starts the local WordPress instance. You may need to run this script multiple times if prompted.
+```
+./bin/setup-local-env.sh
+``` 
+
+If everything was successful, you'll see the following ascii art:
+```
+Welcome to...
+
+,⁻⁻⁻·       .                 |
+|  ،⁓’.   . |---  ,---. ,---. |---. ,---. ,---. ,---.
+|   | |   | |     |---' |   | |   | |---' |     |   |
+`---' `---' `---’ `---’ '   ` `---' `---’ `     `---|
+                                                `---'
+```
 
 The WordPress installation should be available at `http://localhost:8888` (username: `admin`, password: `password`).
 Inside the "docker" directory, you can use any docker command to interact with your containers. If this port is in use, you can override it in your `docker-compose.override.yml` file. If you're running [e2e tests](https://wordpress.org/gutenberg/handbook/reference/testing-overview/#end-to-end-testing), this change will be used correctly.
 
+To bring down this local WordPress instance later run:
+```
+docker-compose down
+```
+
+If you'd like to see your changes reflected in this local WordPress instance, run:
+```
+npm install
+npm run dev
+```
+
 Alternatively, you can use your own local WordPress environment and clone this repository right into your `wp-content/plugins` directory.
 
 Next, open a terminal (or if on Windows, a command prompt) and navigate to the repository you cloned. Now type `npm install` to get the dependencies all set up. Then you can type `npm run dev` in your terminal or command prompt to keep the plugin building in the background as you work on it.

bin/install-node-nvm.sh

@@ -59,12 +59,8 @@ fi
 
 # Check if the current node version is up to date.
 if [ "$TRAVIS" != "true" ] && [ "$(nvm current)" != "$(nvm version-remote --lts)" ]; then
-	echo -en $(status_message "Updating Node..." )
-	nvm install >/dev/null 2>&1
-	echo ' done!'
-
-	echo -e $(warning_message "A new node version was installed, please run this command to use it:" )
-	echo -e $(warning_message "$(action_format "nvm use")" )
+	echo -e $(warning_message "Node version does not match the latest long term support version. Please run this command to install and use it:" )
+	echo -e $(warning_message "$(action_format "nvm install")" )
 	echo -e $(warning_message "After that, re-run the setup script to continue." )
 	exit 1
 fi