title: Change x axis origin to a value (not zero) in ggplot2
body: <p>I am working on generating a tornado plot in R. I am using <code>ggplot2</code> package with code like the following:</p>
  
  <pre><code>dat &lt;- structure(list(variable = structure(c(1L, 2L, 3L, 1L, 2L, 3L), .Label = c("# of nodes needed", 
  "# of nodes owned", "cost per node"), class = "factor"), Level = structure(c(2L, 
  2L, 2L, 1L, 1L, 1L), .Label = c("high", "low"), class = "factor"), 
  value = c(-275, -550, -50, 825, 275, 450)), .Names = c("variable", 
  "Level", "value"), row.names = c(NA, -6L), class = "data.frame")
  
  ggplot(dat, aes(fill=Level,variable,value )) +
      geom_bar(position = 'identity',stat = 'identity') + coord_flip()
  </code></pre>
  
  <p>I am curious as to how to change x-axis origin. Right now, the origin is automatically set to zero, and I want to be able to change it to a variable specified numeric value. </p>