How to fix a bundle “nio4r error” on Rails 5.1.6 on mac10.13
问题 I use ruby 2.5.0, rails 5.1.6, rvm 1.29.3 on my project. I find some answer on this post How to fix a bundle install "nio4r error" on Rails 5.0.0,but return the same error. when run rails -v, it return Could not find nio4r-2.3.0 in any of the sources Run `bundle install` to install missing gems. then I run bundle update or bundle , it return Fetching gem metadata from https://rubygems.org/......... Fetching gem metadata from https://rubygems.org/. Resolving dependencies.......................