I'm running a Rails app and getting this error whilst running in Docker.
There are no results on Google for what the cause might be.
The gem doesn't appear in my Gemfile so it must be a dependency of Rails or another gem.
The previous error I was getting was:-
Could not find 'nokogiri' (>= 1.5.9) among 144 total gem(s) (Gem::MissingSpecError)
To resolve this, I added gem install nokogiri to my Dockerfile, which now gives me the title error. Any ideas?