title: Ruby on Rails: Gem Dependency Issues
body: <p>I am trying to install the most recent version of <strong>haml</strong>, <strong>simple_form</strong>, and <strong>devise</strong> to my Ruby on Rails application, but I cannot seem to get them working with the Bundler tool. How should I proceed in order to get past the dependency issues?</p>
  
  <p>This is the error raised by the Bundler tool:</p>
  
  <p>Bundler could not find compatible versions for gem "activemodel":</p>
  
  <pre><code>  In snapshot (Gemfile.lock):
      activemodel (= 5.1.1)
  
    In Gemfile:
      rails (~&gt; 5.1.1) was resolved to 5.1.1, which depends on
        activemodel (= 5.1.1)
  
      rails (~&gt; 5.1.1) was resolved to 5.1.1, which depends on
        activemodel (= 5.1.1)
  
      simple_form (~&gt; 3.4) was resolved to 3.4.0, which depends on
        activemodel (&lt; 5.1, &gt; 4)
  
      web-console (&gt;= 3.3.0) was resolved to 3.5.1, which depends on
        activemodel (&gt;= 5.0)
  </code></pre>