adding some docs on local setup
adding some docs on local setup

FredericHeem/go-horizon,irisli/horizon,masonforest/horizon,irisli/horizon,masonforest/go-horizon,stellar/horizon,lackac/horizon,lackac/horizon,irisli/horizon,FredericHeem/go-horizon,masonforest/horizon,nullstyle/go-horizon,FredericHeem/go-horizon,masonforest/horizon,lackac/horizon,stellar/horizon,stellar/horizon,nullstyle/go-horizon,nullstyle/go-horizon,masonforest/go-horizon,masonforest/go-horizon