title: ggplot with 2 y axes on each side and different scales
body: <p>I need to plot a bar chart showing counts and a line chart showing rate all in one chart, I can do both of them separately, but when I put them together, I scale of the first layer (i.e. the <code>geom_bar</code>) is overlapped by the second layer (i.e. the <code>geom_line</code>).</p>
  
  <p>Can I move the axis of the <code>geom_line</code> to the right?</p>