title: How can I plot the residuals of lm() with ggplot?
body: <p>I would like to have a nice plot about residuals I got from an <code>lm()</code> model. Currently I use <code>plot(model$residuals)</code>, but I want to have something nicer. If I try to plot it with ggplot, I get the error message: </p>
  
  <blockquote>
    <p>ggplot2 doesn't know how to deal with data of class numeric</p>
  </blockquote>