title: Your Ruby version is 2.1.2, but your Gemfile specified 2.1.5
body: <p>I have this</p>
  
  <pre><code># Gemfile
  source 'https://rubygems.org'
  ruby '2.1.5'
  </code></pre>
  
  <p>and</p>
  
  <pre><code>#.ruby-version
  
  2.1.5
  </code></pre>
  
  <p>and this</p>
  
  <pre><code>$ rvm list
  
  rvm rubies
  
     ruby-1.9.3-p484 [ x86_64 ]
     ruby-2.0.0-p451 [ x86_64 ]
     ruby-2.1.0 [ x86_64 ]
     ruby-2.1.1 [ x86_64 ]
     ruby-2.1.2 [ x86_64 ]
     ruby-2.1.3 [ x86_64 ]
   * ruby-2.1.5 [ x86_64 ]
  </code></pre>
  
  <p>And yet I keep getting this:</p>
  
  <pre><code>$ rails s
  Your Ruby version is 2.1.2, but your Gemfile specified 2.1.5
  </code></pre>
  
  <p>Ruby 2.1.5 is installed.</p>
  
  <pre><code>Already installed ruby-2.1.5.
  To reinstall use:
  
      rvm reinstall ruby-2.1.5
  
  
  
  ruby - v
  ruby 2.1.2p95
  $ rvm use --default 2.1.5
  Using /home/alex/.rvm/gems/ruby-2.1.5
  </code></pre>
  
  <p>But then when I open a new tab or terminal, it reverts back to 2.1.2</p>
  
  <pre><code>ruby - v
  ruby 2.1.2p95
  </code></pre>