Set mysql2 version '~> 0.4.0' to fix rails-429-mysql CI builds
Set mysql2 version '~> 0.4.0' to fix rails-429-mysql CI builds

Active Record 4.2.9 does not support mysql2 greater than or equal to v0.5.0

gocardless/statesman,gocardless/statesman,timothyp/statesman,timothyp/statesman