Readme is not up to date

[akshatpaul]

I found readme is outdated for spree version 3.x

[damianlegawiec]

@akshatpaul any specific issues?

[akshatpaul]

@damianlegawiec Getting too many errors to set up with Spree 3.x and rails 5. But closed the issue coz stack overflow would be better place for that.
Apologies for raising it here.