Updates for Ruby 3.0.0 and 1st time run

Added webrick to gemfile, needed in for Jekyll on ruby 3.x  (jekyll/jekyll#8523)
Also added bundle install to the readme guide for 1st time users

Author: sammachin

Gemfile

@@ -9,3 +9,5 @@ git_source(:github) {|repo_name| "https://github.com/#{repo_name}" }
 gem "jekyll-paginate", "~> 1.1"
 
 gem "jekyll-redirect-from", "~> 0.16.0"
+
+gem "webrick", "~> 1.7"

README.md

@@ -19,9 +19,10 @@ Fork the repository so you can make changes, commit them to your own repository
 
     git clone https://github.com/{your-github}/node-red.github.io
 
-Then run jekyll:
+First time you run jeykll you need to do bundle install 1st for the dependencies, 
 
     cd node-red.github.io
+    bundle install 
     jekyll serve -w
 
 Once the site is built and running you can preview it at [`http://127.0.0.1:4000/`](http://127.0.0.1:4000/).