title: Barplot using ggplot
body: <p>I have a data frame like</p>
  
  <pre><code>  Model1    Model2      Model3    Model4
        4          4          5         5
        4          4         NA        NA
        3          2          5         5
        2          2          3         3
        3          3          3         3
        3          3          4         4
  </code></pre>
  
  <p>I want to plot a barplot like</p>
  
  <p><img src="https://i.stack.imgur.com/sJhYj.png" alt="enter image description here"></p>
  
  <p>The x- axis will have the Model1,Model2,Model3 and Model4 and the bars will be the proportion of the scores in each column,i.e., 6 bars for each Model (in the full data I have the scores from 0 to 5)</p>
  
  <p>How can this be done without having to create a dataframe using rbind or creating a matrix?
  Any help will be appreciated.</p>