title: position dodge not working with geom bar plot
body: <p>I have this bar plot</p>
  
  <pre><code>group = c("A","A","B","B")
  value = c(1,2,3,4)
  day = c(1,2,1,2)
  dat = data.frame(group = group , value = value, day = day)
  dat
  
  ggplot(data=dat, aes(x = group, y = value, fill = day)) +
      geom_bar(stat = "identity", position = "dodge")
  </code></pre>
  
  <p>and it is stacked but I don't want it stacked. Instead I'd like to use <code>position = "dodge"</code> to make the days stacked next to each other FOR EACH group.  any idea how to get the days next to each other for each group?</p>