title: Fix conflict between rails executable "rails" and railties
body: <p>Trying to switch from rails 3.2.13 to 3.1, using RVM 1.22.3.</p>
  
  <p>Using ruby 1.9.3.</p>
  
  <p>Did the following:</p>
  
  <pre><code>$ rvm gemset create rails31
  gemset created rails31  =&gt; /Users/mwsage/.rvm/gems/ruby-1.9.3-p429@rails31
  $ rvm 1.9.3-p429@rails31
  $ gem install -v3.1 rails
  </code></pre>
  
  <p>After fetching and successfully installing many gems, I am prompted with this:</p>
  
  <pre><code>rails's executable "rails" conflicts with railties
  Overwrite the executable? [yN]
  </code></pre>
  
  <p>I chose no.</p>
  
  <p>Then</p>
  
  <pre><code>$ rails -v
  Rails 3.1.0
  </code></pre>
  
  <p>Am I fully set up? How do I resolve this conflict if I need to? </p>