Unable to run merge_vars:sync rake task

[Hugoandmarie20]

I'm getting the same error as previously reported, with Spree 3.1. I also tried bundle exec, but no luck.

Thank you.

rake aborted!
NameError: uninitialized constant Spree::Chimpy::Config
/Users/sarahana/.rvm/gems/ruby-2.2.2/bundler/gems/spree_chimpy-1763ad974109/lib/spree_chimpy.rb:25:in `configured?'
/Users/sarahana/.rvm/gems/ruby-2.2.2/bundler/gems/spree_chimpy-1763ad974109/lib/spree_chimpy.rb:45:in `list'
/Users/sarahana/.rvm/gems/ruby-2.2.2/bundler/gems/spree_chimpy-1763ad974109/lib/spree_chimpy.rb:69:in `sync_merge_vars'
/Users/sarahana/.rvm/gems/ruby-2.2.2/bundler/gems/spree_chimpy-1763ad974109/lib/tasks/spree_chimpy.rake:5:in `block (3 levels) in <top (required)>'
/Users/sarahana/.rvm/gems/ruby-2.2.2/gems/rake-12.0.0/exe/rake:27:in `<top (required)>'
/Users/sarahana/.rvm/gems/ruby-2.2.2/bin/ruby_executable_hooks:15:in `eval'
/Users/sarahana/.rvm/gems/ruby-2.2.2/bin/ruby_executable_hooks:15:in `<main>'
Tasks: TOP => spree_chimpy:merge_vars:sync
(See full trace by running task with --trace)