Add Installation Instructions for Ubuntu (#6925)
Add Installation Instructions for Ubuntu (#6925)

Merge pull request 6925
x-way/jekyll,jekyll/jekyll,jaybe-jekyll/jekyll,jaybe-jekyll/jekyll,fulldecent/jekyll,jaybe-jekyll/jekyll,Strangehill/jekyll,jekyll/jekyll,ryanshaw/jekyll,jekyll/jekyll,chrisfinazzo/jekyll,Strangehill/jekyll,getandpost/jekyll.github.io,tillgrallert/jekyll,Strangehill/jekyll,Strangehill/jekyll,ryanshaw/jekyll,x-way/jekyll,fulldecent/jekyll,ryanshaw/jekyll,chrisfinazzo/jekyll,fulldecent/jekyll,tillgrallert/jekyll,getandpost/jekyll.github.io,chrisfinazzo/jekyll,fulldecent/jekyll,jaybe-jekyll/jekyll,yhironaka/yhironaka.github.io,getandpost/jekyll.github.io,Strangehill/jekyll,tillgrallert/jekyll,tillgrallert/jekyll,x-way/jekyll,tillgrallert/jekyll,jekyll/jekyll,x-way/jekyll,ryanshaw/jekyll,chrisfinazzo/jekyll