title: how do you put text on different lines in ggplot
body: <p>My df looks like this:</p>
  
  <pre><code> Product       Day      Month Total
  Web Server, Applicatiion Server, Database Server, Middle Tier Tue 2015-01-01  10
  Web Server, Application Server, Database Server, Middle Tier  Wed 2015-01-01    6
  Web Server, Application Server, Database Server, Middle Tier  Wed 2015-02-01    6
  </code></pre>
  
  <p>I need to create a heat map in ggplot2 where I need to insert Product name as geom_text. </p>
  
  <p>I have this so far:</p>
  
  <pre><code>ggplot(cal, aes(x=Month, y=Day, fill=Total)) +
     geom_tile() +
     scale_fill_gradient2(high="red",mid="green",low="yellow", 
         na.value="white", midpoint=mean(cal$Total, na.rm=T))+scale_x_date(labels = date_format("%b-%Y"), breaks = date_breaks("month"))+
         geom_text(aes(label=Product))
  </code></pre>
  
  <p>What happens is since there are multiple Product names separated by comma, when I do geom_text (aes(label=Product)), text is written on top of each other. </p>
  
  <p>Is it possible put each Product name on different lines?</p>