title: Rails form only show future dates in datetime select field
body: <p>I have a form that I've made using simple_form, one of the fields in the form is a datetime. I'd like to limit it so that users can only select dates that are after the datetime as of now so they can't create records for the past. </p>
  
  <p>I've experimented doing this with validations but I'd just like to limit the form options instead. I limited the hour range to what I wanted but can't find something similar for days.</p>
  
  <p>The form for the event</p>
  
  <pre><code>&lt;%= simple_form_for @event do |f| %&gt;
  
    &lt;%-# Form input fields -%&gt;
    &lt;%= f.input :name, label: 'Title' %&gt;
    &lt;%= f.input :event_date, minute_step: 15, start_hour: 7, end_hour: 21 %&gt;
    &lt;%= f.input :body %&gt;
    &lt;%= f.submit 'Submit' , :class =&gt; "btn btn-primary" %&gt;
  
  &lt;% end %&gt;
  </code></pre>