title: Plots not showing in ggplot2 with geom_bar
body: <p>I am trying to plot stacked bars using <code>ggplot()</code> and <code>geom_bar()</code></p>
  
  <p>Sample data (Titanic Kaggle question):</p>
  
  <pre><code>PassengerId   Survived   Age
            1          0    25
            2          1    20
            3          1    40
            4          0    10
  </code></pre>
  
  <p>I am trying to show stacked bars of survival and death for each age range (I have divided age into bins). Plot is not visible when I execute the command. and when I add print() function, I get the error as </p>
  
  <blockquote>
    <p>Error: No layers in plot</p>
  </blockquote>
  
  <p>Please tell if there is anything I am missing out here ?</p>
  
  <pre><code>breaks &lt;- seq(min(train$Age), max(train$Age), 10)
  p &lt;- ggplot(train, aes(x=train$Age, y=length(train$PassengerId)), xlab = "age", ylab = "count", main = "survival", 
     fill = Survived + geom_bar(stat = "identity", bin = breaks))
  
  print(p)
  </code></pre>
  
  <p>"train" is object in which I stored the data.</p>