title: Why should we avoid using class variables @@ in rails?
body: <p>Why should we avoid using class variables @@ in rails? Is there any security loopholes with that. Please answer as I am new with rails. and I am much using instance variable <code>@variable_name</code> . I tried once <code>@@variable_name</code> .</p>
  
  <p>I know only about class variable is, <em>Class variable is sharable between object</em></p>
  
  <p>But I really would like to know  <strong>Why should we avoid using class variables @@ in rails?</strong></p>