add notes about rackup, fixes #313
add notes about rackup, fixes #313

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