nav generated by gem exists in dom but not visible to the eye

[Sam W]

I initially filed this issue thinking it's a bootstrap alpha issue.
So I re-did my but this time sticking to the bootstrap version you guys recommend in README.
Still my nav is not visible.
Rails 5.2 Ruby 2.5.1

Any chance of making the gem work with plain old bootstrap gem (4.1.3)
gem 'bootstrap'
I don't feel great installing an alpha version as mentione in README
gem 'bootstrap', '~> 4.0.0.alpha3.1'