title: Using of session in Ruby on Rails
body: <p>I have understood that the use of session is like using a Hash (more or less). When I use the session I set something like session[:sort] = 'title'. However, the app throws me an exception:</p>
  
  <p>undefined local variable or method `session' for MoviesController:Class</p>
  
  <p>That makes me think that I have to set something before I use session, like initialize it. Any ideas? Thanks!</p>