Added Rails, PHP, and better RVM instructions to README
Added Rails, PHP, and better RVM instructions to README

CloCkWeRX/mailcatcher,MacroMackie/mailcatcher,intentmedia/mailcatcher-jruby,TuffLuck/mailcatcher,okinaka/mailcatcher,Noxa/mailcatcher,sj26/mailcatcher,saisai/mailcatcher,TuffLuck/mailcatcher,MacroMackie/mailcatcher,sj26/mailcatcher,okinaka/mailcatcher,globaldev/mailcatcher,saisai/mailcatcher,intentmedia/mailcatcher-jruby,globaldev/mailcatcher,iFixit/mailcatcher,iFixit/mailcatcher,SilverCG/mailcatcher,excepttheweasel/mailcatcher,SilverCG/mailcatcher,Noxa/mailcatcher