title: gam plots with ggplot
body: <p>I need to create some gam plots in ggplot. I can do them with the general plot function, but am unsure how to do with ggplot.  Here is my code and plots with the regular plot function. I'm using the College data set from the ISLR package.</p>
  
  <pre><code>train.2 &lt;- sample(dim(College)[1],2*dim(College)[1]/3)
  train.college &lt;- College[train.2,]
  test.college &lt;- College[-train.2,]
  gam.college &lt;- gam(Outstate~Private+s(Room.Board)+s(Personal)+s(PhD)+s(perc.alumni)+s(Expend)+s(Grad.Rate), data=train.college)
  par(mfrow=c(2,2))
  plot(gam.college, se=TRUE,col="blue")
  </code></pre>