clarify docker docs re data dir at build time

add node12 as recommended (as well as 10)

Author: Dave Conway-Jones

docs/faq/node-versions.md

@@ -5,7 +5,7 @@ title: Supported Node versions
 slug: node versions
 ---
 
-Node-RED currently recommends **Node 10.x LTS**.
+Node-RED currently recommends **Node 10.x LTS** or **Node 12.x LTS**.
 
 Version | Support Level | Notes
 --------|---------------|------
@@ -14,7 +14,9 @@ Version | Support Level | Notes
  9.x  | *Unsupported* |
  **10.x**  | **Recommended** |
   11.x  | *Unsupported* |
-  **12.x**  | **Supported** |  
+  **12.x**  | **Recommended** |  
+  13.x  | *Unsupported* |
+  **14.x**  | **Supported** |  
 
 
 We try to stay up to date with Node.js releases. Our goal is to support

docs/getting-started/docker.md

@@ -221,29 +221,35 @@ It can sometimes be useful to populate a Node-RED Docker image with files from a
 ```
 Dockerfile
 README.md
+package.json     # add any extra nodes your flow needs into your own package.json.
 flows.json       # the normal place Node-RED store your flows
 flows_cred.json  # credemtials your flows may need
-package.json     # the non-standard modules your flows use
-settings.js      # the normal settings file
+settings.js      # your settings file
 ```
 
+**NOTE**: This method is NOT suitable if you want to mount the /data volume externally. If you need to use an external volume for persistence then copy your settings and flows files to that volume instead.
+
 The following Dockerfile builds on the base Node-RED Docker image, but additionally moves your own files into place into that image:
 
 ```
 FROM nodered/node-red
 
 # Copy package.json to the WORKDIR so npm builds all
-# of your added modules for Node-RED
+# of your added nodes modules for Node-RED
 COPY package.json .
-RUN npm install --only=production
+RUN npm install --unsafe-perm --no-update-notifier --no-fund --only=production
 
 # Copy _your_ Node-RED project files into place
+# NOTE: This will only work if you DO NOT later mount /data as an external volume.
+#       If you need to use an external volume for persistence then
+#       copy your settings and flows files to that volume instead.
 COPY settings.js /data/settings.js
 COPY flows_cred.json /data/flows_cred.json
 COPY flows.json /data/flows.json
 
-# Start the container normally
-CMD ["npm", "start"]
+# You should add extra nodes via your package.json file but you can also add them here:
+#WORKDIR /usr/src/node-red
+#RUN npm install node-red-node-smooth
 ```
 
 #### Dockerfile order and build speed