Tweak README formatting; move community/contributing to website
Tweak README formatting; move community/contributing to website

ktw1222/sinatra,marocchino/sinatra,ktw1222/sinatra,guidohcosta/sinatra,blambeau/sinatra,lastcat/sinatra,ksw2599/sinatra,gferguson-gd/sinatra,trexnix/sinatra,porras/sinatra,laplaceliu/sinatra,QLGu/sinatra,ryanshaw/sinatra,davydovanton/sinatra,nju520/sinatra,eileencodes/sinatra,JonRowe/sinatra,guidohcosta/sinatra,Callygraphy/morrissey,sinatra/sinatra,emiliocorpus/sinatra,jenalgit/sinatra,kyontan/sinatra,defsprite/sinatra,frechei/sinatra,laplaceliu/sinatra,bmizerany/sinatra,midorineko/sinatra,miyazawatomoka/sinatra,sethuster/sinatra,howtolearntocode/sinatra,ABaldwinHunter/sinatra-classic,ksw2599/sinatra,gferguson-gd/sinatra,Wirachmat/sinatra,mwpastore/sinatra,RosenDimov/sinatra,JonMidhir/sinatra,DoraALin/sinatra,miyazawatomoka/sinatra,ABaldwinHunter/sinatra-classic,kyontan/sinatra,kumji/sinatra,nju520/sinatra,Rayheng/sinatra,dariubs/sinatra,mwpastore/sinatra,ryanshaw/sinatra,davydovanton/sinatra,dariubs/sinatra,autopp/sinatra,autopp/sinatra,Wirachmat/sinatra,sethuster/sinatra,d-bot/sinatra,wzheng1/sinatra,burningTyger/sinatra,nottombrown/old-sinatra,jkowens/sinatra,nicoayala/sinatra,frechei/sinatra,twanies/sinatra,howtolearntocode/sinatra,JonRowe/sinatra,JonMidhir/sinatra,jkowens/sinatra,kumji/sinatra,cyberid41/sinatra,nottombrown/old-sinatra,mwpastore/sinatra,eileencodes/sinatra,JonMidhir/sinatra,Rayheng/sinatra,burningTyger/sinatra,midorineko/sinatra,wzheng1/sinatra,burningTyger/sinatra,ganmacs/sinatra,sinatra/sinatra,QLGu/sinatra,DoraALin/sinatra,jenalgit/sinatra,nicoayala/sinatra,trexnix/sinatra,porras/sinatra,defsprite/sinatra,kgrz/sinatra,jkowens/sinatra,cyberid41/sinatra,emiliocorpus/sinatra,siberianbear/sinatra,lastcat/sinatra,RosenDimov/sinatra,ganmacs/sinatra,d-bot/sinatra,siberianbear/sinatra,twanies/sinatra