title: Bundler misses gems on Mac
body: <p>I have problems loading gems with bundler. Happens only in my mac environment. The gem cannot be found via bundler, but when I install the gem globally via <code>gem install #{gem}</code> it works.</p>
  
  <p>I suppose this is something environment specific, but I am not sure how to debug it. I have the same versions of ruby, ruby-install and chruby and bundler on a Ubuntu box, but it works just fine.</p>
  
  <p>So far I had this problem with the gems spring-comands-rspec and rack-cors.</p>
  
  <p>Broken environment (Mac):</p>
  
  <pre><code>OS: Darwin nb-mjacobus2 16.7.0 Darwin Kernel Version 16.7.0: Thu Jun 15 17:36:27 PDT 2017; root:xnu-3789.70.16~2/RELEASE_X86_64 x86_64
  Bundler: 1.15.4
  ruby-install: 0.6.1
  chruby: 0.3.9
  ruby: ruby 2.4.1p111 (2017-03-22 revision 58053) [x86_64-darwin16]
  </code></pre>
  
  <h2>Exposing the error:</h2>
  
  <p>Gemfile</p>
  
  <pre><code>group :development do
    # ...
    gem 'spring-commands-rspec'
    # ...
  end
  </code></pre>
  
  <p>Running tests</p>
  
  <pre><code>./bin/rspec spec/controller/some_controller_spec.rb:8
  /$HOME/.rubies/ruby-2.4.1/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file -- spring-commands-rspec (LoadError)
          from /$HOME/.rubies/ruby-2.4.1/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
          from /$HOME/.spring.rb:2:in `&lt;top (required)&gt;'
          from /$HOME/.rubies/ruby-2.4.1/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
          from /$HOME/.rubies/ruby-2.4.1/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
          from /$HOME/.gem/ruby/2.4.1/gems/spring-2.0.2/lib/spring/commands.rb:29:in `&lt;module:Spring&gt;'
          from /$HOME/.gem/ruby/2.4.1/gems/spring-2.0.2/lib/spring/commands.rb:4:in `&lt;top (required)&gt;'
          from /$HOME/.rubies/ruby-2.4.1/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
          from /$HOME/.rubies/ruby-2.4.1/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
          from /$HOME/.gem/ruby/2.4.1/gems/spring-2.0.2/lib/spring/server.rb:9:in `&lt;top (required)&gt;'
          from /$HOME/.rubies/ruby-2.4.1/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
          from /$HOME/.rubies/ruby-2.4.1/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
          from /$HOME/.gem/ruby/2.4.1/gems/spring-2.0.2/lib/spring/client/server.rb:9:in `call'
          from /$HOME/.gem/ruby/2.4.1/gems/spring-2.0.2/lib/spring/client/command.rb:7:in `call'
          from /$HOME/.gem/ruby/2.4.1/gems/spring-2.0.2/lib/spring/client.rb:30:in `run'
          from /$HOME/.gem/ruby/2.4.1/gems/spring-2.0.2/bin/spring:49:in `&lt;main&gt;'
  </code></pre>
  
  <p>Manually installing the gem solves the problem....</p>
  
  <pre><code>gem install spring-commands-rspec
  Fetching: spring-commands-rspec-1.0.4.gem (100%)
  Successfully installed spring-commands-rspec-1.0.4
  Parsing documentation for spring-commands-rspec-1.0.4
  Installing ri documentation for spring-commands-rspec-1.0.4
  Done installing documentation for spring-commands-rspec after 0 seconds
  1 gem installed
  </code></pre>
  
  <p>... BUT I get this warnings:</p>
  
  <pre><code>./bin/rspec spec/pattern_library_controller_spec.rb
  WARN: Unresolved specs during Gem::Specification.reset:
        minitest (~&gt; 5.1)
  WARN: Clearing out unresolved specs.
  Please report a bug if this causes problems.
  WARN: Unresolved specs during Gem::Specification.reset:
        minitest (~&gt; 5.1)
  WARN: Clearing out unresolved specs.
  Please report a bug if this causes problems.
  Running via Spring preloader in process 53164
  Run options: include {:focus=&gt;true}
  
  All examples were filtered out; ignoring {:focus=&gt;true}
  
  Randomized with seed 5284
  
  SomeController
    should respond with a success status code (2xx)
  
  Finished in 0.13193 seconds (files took 0.66951 seconds to load)
  1 example, 0 failures
  
  Randomized with seed 5284
  </code></pre>
  
  <p>Any idea what the problem could be?</p>