title: Travis CI, unable to run tests - Error: activesupport requires Ruby version >= 2.2.2
body: <p>I have an open sourced <code>Obj-C</code> <a href="https://github.com/EvgenyKarkan/EKAlgorithms" rel="nofollow noreferrer">repository</a> with <code>Kiwi</code> unit testing framework as <code>CocoaPods</code> dependency.<br>
  To run tests I'm using <code>Travis CI</code> continious integration tool. </p>
  
  <p>Everything was fine previously, all unit tests were executed, but now I'm getting Travis CI build error:</p>
  
  <pre><code>ERROR:  Error installing cocoapods:
      activesupport requires Ruby version &gt;= 2.2.2.
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/HP7Wi.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/HP7Wi.jpg" alt="enter image description here"></a> </p>
  
  <p>Here is my <code>.travis.yml</code> file:</p>
  
  <pre><code>language: objective-c
  
  before_install:
  - sw_vers
  - cd EKAlgorithmsApp
  
  install: make install
  
  script: make ci
  </code></pre>
  
  <p>And here is my <code>Makefile</code>: </p>
  
  <pre><code>install:
      gem install cocoapods --no-ri --no-rdoc
      gem install xcpretty  --no-ri --no-rdoc
      pod install
  
  ci:
      xcodebuild -workspace EKAlgorithmsApp.xcworkspace/ -scheme EKAlgorithmsSpecs -sdk macosx -configuration Release clean test | xcpretty -c
  </code></pre>
  
  <p>It seems that something in configurations has changed on Travis CI side, but I'm not very familiar with Ruby, so I need a help of how to fix that warning to run my tests successfully.</p>