title: cannot load such file middleman-core - (middleman server)
body: <p>I've installed all prerequisites for middleman project to proceed further 
   but at <code>middleman server</code> causing an issue
  what actually it is said to me </p>
  
  <blockquote>
    <p>PS C:\First_MP> middleman server
    C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/middleman-cli-4.1.7/bin/middleman:12:in <code>require': cannot load such file -- middleman-core (LoadError)
    from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/middleman-cli-4.1.7/bin/middleman:12:in</code><code>
            from C:/Ruby22-x64/bin/middleman:23:in</code>load'
            from C:/Ruby22-x64/bin/middleman:23:in `'</p>
  </blockquote>
  
  <p>I need to know what I'm missing or need to change that my project will run</p>
  
  <p>Directories in my PC.
  Ruby:</p>
  
  <pre><code>C:\Ruby22-x64
  </code></pre>
  
  <p>and 
  DevKit:</p>
  
  <pre><code>C:\Ruby22-x64\RubDevKit
  </code></pre>
  
  <p>creating Project </p>
  
  <pre><code>C:\ middleman init First_MP
  </code></pre>
  
  <p>ruby -v</p>
  
  <pre><code>ruby 2.2.4p230 (2015-12-16 revision 53155) [x64-mingw32]
  </code></pre>
  
  <p>and Dev kit</p>
  
  <pre><code>DevKit-mingw64-64-4.7.2-20130224-1432-sfx
  </code></pre>