title: How to make Graphviz's dot executable path available in my rails application
body: <p>Please i am new to rails a i want to generate an ER diagram for my application, i found that using <strong>rails-erd gem</strong> was an option which depended on <strong>Graphviz</strong> i have install the Graphviz application but can't figure out a way to make it visible in my rails application. I get the following error each time i run <code>rake erd</code> in my rails application.</p>
  
  <pre><code>$ rails erd
  rails aborted!
  Unable to find GraphViz's "dot" executable. Please visit 
  https://voormedia.github.io/rails-erd/install.html for installation 
  instructions.
  bin/rails:4:in `require'
  bin/rails:4:in `&lt;main&gt;'
  Tasks: TOP =&gt; erd =&gt; erd:generate =&gt; erd:check_dependencies
  (See full trace by running task with --trace)
  </code></pre>