Improve instructions to build from source
Improve instructions to build from source

This commit refactors the instructions on how to create a project
using github source to make it more explicit and easier to follow for
new comers.

CultivateHQ/phoenix,wsmoak/phoenix,mitchellhenke/phoenix,phoenixframework/phoenix,pap/phoenix,pap/phoenix,ybur-yug/phoenix,jwarwick/phoenix,ericmj/phoenix,Ben-Evolently/phoenix,jwarwick/phoenix,wsmoak/phoenix,rafbgarcia/phoenix,jamilabreu/phoenix,phoenixframework/phoenix,evax/phoenix,stevedomin/phoenix,dmarkow/phoenix,keathley/phoenix,optikfluffel/phoenix,eksperimental/phoenix,rafbgarcia/phoenix,0x00evil/phoenix,nshafer/phoenix,nshafer/phoenix,mobileoverlord/phoenix,gjaldon/phoenix,evax/phoenix,mschae/phoenix,michalmuskala/phoenix,nshafer/phoenix,iStefo/phoenix,Gazler/phoenix,Gazler/phoenix,trarbr/phoenix,mschae/phoenix,optikfluffel/phoenix,bsmr-erlang/phoenix,0x00evil/phoenix,gjaldon/phoenix,Joe-noh/phoenix,stevedomin/phoenix,rafbgarcia/phoenix,jamilabreu/phoenix,korobkov/phoenix,Joe-noh/phoenix,mitchellhenke/phoenix,michalmuskala/phoenix,dmarkow/phoenix,Kosmas/phoenix,ericmj/phoenix,ephe-meral/phoenix,mobileoverlord/phoenix,keathley/phoenix,iStefo/phoenix,Kosmas/phoenix,phoenixframework/phoenix,ybur-yug/phoenix,ephe-meral/phoenix,eksperimental/phoenix,optikfluffel/phoenix,cas27/phoenix,trarbr/phoenix,bsmr-erlang/phoenix,korobkov/phoenix,cas27/phoenix,0x00evil/phoenix,CultivateHQ/phoenix