title: How to store data in cache in symfony2
body: <p>I have a configuration-table(id,name,value), containing some configuration variables for my symfony application such as email_expiration_duration. I want to write a service to read these configuration varibales from symfony application.</p>
  
  <p>I want cache the data in app/cache folder.
  That means I will read the data from database only if the data is not in cache.
  I will clear the cached data whenever the configuration value changes.</p>
  
  <p>How can I do it in symfony2?</p>