title: Two different ruby versions on mac?
body: <p>I am setting up a simple ruby on rails app locally. It seems I have two different versions of ruby on mac and I would like to only use one. When I ran <code>bundle install</code>, it says <code>Your Ruby version is 2.7.1, but your Gemfile specified 2.6.3</code>. Then, I changed the line <code>ruby '2.6.3'</code> in my gemfile to <code>ruby '2.7.1'</code>. With this it ran <code>bundle install</code> properly. However, when I run <code>rails server</code> it says <code>Your Ruby version is 2.6.3, but your Gemfile specified 2.7.1</code>.<br><br>
  Why is it saying two different values for my Ruby version?
  How do I get it to only use one version of Ruby?
  <br><br>
  If its relevant, I am on a mac and installed ruby using homebrew. If I run <code>ruby -v</code> in the terminal it says <code>ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [x86_64-darwin19]</code>. I'm not sure why it says I have ruby 2.6.3.</p>