Add symlink for node under Unix.

README.md

@@ -22,9 +22,14 @@ sudo apt install npm
 npm install --global npm@latest
 ```
 
+- Under Unix, create a symbolic link for `node`
+```
+sudo ln -s /usr/bin/nodejs /usr/bin/node
+```
+
 - Install Yeoman, bower and grunt
 ```
-npm install --global yo
+sudo npm install --global yo
 npm install -g generator-reveal
 npm install -g grunt-cli
 npm install -g bower