title: SweetAlert dropdown dynamically add items in list
body: <p>I am currently using sweetalert2 to capture user's input from the dialog. I would like to use the dropdown in chaining queue dialog but I can't seem to find a way to dynamically add items in the dropdown list. Let's say I want to retrieve data from JSON format and place in the dropdown list, is there a way to do it?</p>
  
  <pre><code>function userInput() {
      swal.setDefaults(
          {
              showLoaderOnConfirm: true,
              confirmButtonText: 'Next &amp;rarr;',
              showCancelButton: true,
              animation: true,
              progressSteps: ['1', '2', '3']
          }
      );
  
      var steps = [
          {
              text: 'Select an author to analyze the commit',
              input: 'select',
              inputOptions: {
                  'SRB': 'Serbia',     // How do I dynamically set value?
                  'UKR': 'Ukraine',
                  'HRV': 'Croatia'
              }
          },
          {
              text: 'Select multiple authors to compare their commits',
              input: 'select',
              inputOptions: {
                  'SRB': 'Serbia',      // How do I dynamically set value?
                  'UKR': 'Ukraine',
                  'HRV': 'Croatia'
              }
          },
          {
              text: 'Select a file directory to analyze all author\'s commit',
              input: 'select',
              inputOptions: {
                  'SRB': 'Serbia',      // How do I dynamically set value?
                  'UKR': 'Ukraine',
                  'HRV': 'Croatia'
              }
          }
      ];
  
      swal.queue(steps).then(function(result) {
          swal.resetDefaults();
          swal({
              type: 'success',
              title: 'Success',
              text: 'Scroll down for statistics!',
              html:
                  'Your selections: &lt;pre&gt;' +
                  JSON.stringify(result) +
                  '&lt;/pre&gt;',
              confirmButtonText: 'Ok',
              showCancelButton: false
          })
      }, function() {
          swal.resetDefaults()
      })
  }
  </code></pre>
  
  <p>Retrieve data in JSON format:</p>
  
  <pre><code>function getData(repolink) {
   readDataFromGit('https://api.github.com/repos/' + repolink + '/git/trees/master?recursive=1', function(text){
          data = JSON.parse(text);
          $.each(data, function(i, v) {
              // Retrieve v.login data!
              data = v.login;
          })
      });
  }
  
  function readDataFromGit(link, callback) {
      var request = new XMLHttpRequest();
      request.overrideMimeType("application/json");
      request.open('GET', link, true);
      request.onreadystatechange = function() {
          if (request.readyState === 4 &amp;&amp; request.status == "200") {
              callback(request.responseText);
          }
      };
      request.send(null);
  }
  </code></pre>