small changes to Environment section and minor markup fixes
small changes to Environment section and minor markup fixes

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