gettext:compile fails on Ruby 2.5.1

bundle exec rake gettext:compile


rake aborted!
NoMethodError: undefined method `join' for nil:NilClass
Traceback (most recent call last):
/home/axil/.rvm/gems/ruby-2.5.1/bin/ruby_executable_hooks: undefined method `reject' for nil:NilClass (NoMethodError)

It appears gettext is not supported for Ruby 2.5.1, I opened an issue upstream https://github.com/ruby-gettext/gettext/issues/59.