title: How to pass symbol as parameter of post request in ruby?
body: <p>This code work well</p>
  
  <pre><code>Geokit::default_units = :miles #:kms, :nms, :meters
  </code></pre>
  
  <p>But this code make errors</p>
  
  <pre><code>puts params[:unit]     # miles
  Geokit::default_units = params[:unit] #:miles, :kms, :nms, :meters
  </code></pre>
  
  <p>What is wrong with this?</p>