title: Change color of overlayed bar graphs ggplot2
body: <p>I've plotted two bar graphs on top of each other using the following:</p>
  
  <pre><code>library(ggplot2)
  library(reshape2)
  
  
  x = c("type1", "type2", "type3")
  y1 = c("1","2","3")
  y2 = c("2","3","4")
  
  to_plot &lt;- data.frame(x=x,y1=y1,y2=y2)
  melted&lt;-melt(to_plot, id="x")
  
  ggplot() + geom_bar(data=melted,aes(x=x,y=value,fill=variable),stat="identity",position = "identity", alpha=.3)
  </code></pre>
  
  <p>This gave me the following output:
  <a href="https://i.stack.imgur.com/tQoJb.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/tQoJb.png" alt="enter image description here"></a></p>
  
  <p>Is there anyway I can change the color of the bar graphs? For example, I would like the y1 graph to be the same grey as the background</p>