title: how to insert a button to open modal window inside a simple_form
body: <p>using Rails 4.1.6 , simple_form 3.1.0.rc2, Bootstrap 3
  I am trying to set a button inside my simple_form to open a Bootsrap modal window to perform a js user selection </p>
  
  <p>my simple form is the following :</p>
  
  <pre><code>.form-inputs
    .row
      .col-sm-8.col-md-8.col-lg-8
          - if ((current_user.has_role? :superadmin) || (current_user.has_role? :media_admin)) 
              .form-group
                  %button.btn.btn-default{:'data-toggle' =&gt; "modal" , :'data-target' =&gt; "#myModal"}
                      Select Owner of album
          = f.input :user_id, as: :hidden, input_html: {value: current_user.id}
  
    .row
      .col-sm-8.col-md-8.col-lg-8
          = f.input :title, :label =&gt; t(:title, scope: :album).capitalize
          = f.input :description, as: :text, :label =&gt; t(:description, scope: :album).capitalize
  </code></pre>
  
  <p>and I added a  standard bootstrap modal test</p>
  
  <pre><code>            #myModal.modal.fade{ tabindex: "-1" ,role: "dialog", :'aria-labelledby' =&gt; "myModalLabel",  :'aria-hidden' =&gt; "true"}
              .modal-dialog
                  .modal-content
                      .modal-header
                          %button.close{type: "button",  :'data-dismiss' =&gt; "modal" }
                              %span{:'aria-hidden' =&gt; true}
                                  &amp;times;
                              %span.sr-only
                                  Close
                          %h4#myModalLabel.modal-title
                              Modal Title
                      .modal-body
                          = "Modal body"
                      .modal-footer
                          %button.btn.btn-default{type: "button",  :'data-dismiss' =&gt; "modal" }
                              Close
                          %button.btn.btn-primary{type: "button",  :'data-dismiss' =&gt; "modal" }
                              Save changes
  </code></pre>
  
  <p>When I hit the 'Select Owner of album' button, it acts as the submit one and try to save the form data.... not opening the modal form</p>
  
  <p>Did I miss anything ?</p>