title: How difficult is it to create the functionalities found in Kissmetrics, Mixpanel and Woopra in my Rails App?
body: <p>I wish to "know every person and everything they did." </p>
  
  <p>For the funnel and cohorts, I could probably use Google Analytics. But how if I want a clear overview of who a user is and a whole history of what they have done on my site. </p>
  
  <p>I am working on Ruby on Rails. Is there a gem for this? Is it easy to build it from scratch? </p>