title: Chartjs multiple barcharts corresponding to one label
body: <p>I have a question regarding barcharts in Chartjs.</p>
  
  <p>I want to display multiple barcharts for each label, but it has proven very hard for some reason.</p>
  
  <p>I am building a chart to display the amount of repetitions and sets someone has done, as a function of the date.</p>
  
  <p>So on the X-axis I have the dates - and on the Y-axis I have the amount of repetitions. If the person has done 3 sets that day, it should display 3 bars on that date, where the value (height of the bar) is the number of repetitions.</p>
  
  <p>For testing purposes I have three dates and a few sets/reps for each date:</p>
  
  <p><code>"2017-05-25"
  - Set 1: 7 reps
  "2017-05-30"
  - Set 1: 8 reps
  - Set 2: 9 reps
  - Set 3: 10 reps
  "2017-05-31"
  - Set 1: 3 reps
  - Set 2: 7 reps
  - Set 3: 12 reps
  - Set 4: 8 reps</code></p>
  
  <p>This is my current chartData object.</p>
  
  <pre><code>var chartData = {
        labels: Object.keys(items.dates),
        datasets: [{
             label: "Reps",
             backgroundColor: "blue",
             data: [7]
        }, {
             label: "Reps",
             backgroundColor: "red",
             data: [8, 9, 10]
        }, {
             label: "Reps",
             backgroundColor: "green",
             data: [3, 7, 12, 8]
        }]
  };
  </code></pre>
  
  <p>The dates are displayed correctly, but I can't seem to get the reps/sets right. I believe I somehow have to group them some other way around or something.</p>
  
  <p>All help appreciated!</p>
  
  <p><strong>UPDATE</strong>
  Made a jsfiddle:
  <a href="https://jsfiddle.net/ytkqwL9x/1/" rel="nofollow noreferrer">https://jsfiddle.net/ytkqwL9x/1/</a></p>
  
  <p>As you can see, the sets fall into the wrong dates - in the first date: 2017-05-25, there is supposed to be only 1 set, but it shows 3 (7,8,3).</p>