title: How to install Ruby on docker?
body: <p>I am trying to install ruby on docker. I could install the 1.9 versions but it is not possible to install the latest version such as 2.2.0 and above. I am actually trying to set up calabash on docker. Have tried <a href="https://stackoverflow.com/questions/16222738/how-do-i-install-ruby-2-0-0-correctly-on-ubuntu-12-04">this</a>. Whenever I try to install calabash-android in it getting the error </p>
  
  <pre><code>ERROR:  Error installing calabash-android:
  luffa requires Ruby version &gt;= 2.0.
  </code></pre>