# Gemfile
gem 'bootstrap-sass', '~> 3.3', '>=3.3.6'
gem 'bootstrap-datepicker-rails', '~> 1.6', '>= 1.6.1.1'

# application.css.scss
/*
*= require bootstrap-datepicker3
*= require_tree .
*= require_self
*/
@import "bootstrap-sprockets";
@import "bootstrap";

# application.js
//= require jquery
//= require jquery_ujs
//= require bootstrap-sprockets
//= require bootstrap-datepicker
//= require turbolinks
//= require_tree .

# _form.html.erb
<div class="form-group">
  <%= f.label :start_date %><br>
  <%= f.text_field :start_date, data: {provide: 'datepicker'} %>
</div>

<div class="form-group">
  <%= f.label :end_date %><br>
  <%= f.text_field :end_date, data: {provide: 'datepicker'} %>
</div>

Parameters: {..., "expense_duration"=>{"start_date"=>"05/10/2016", "end_date"=>"06/22/2016"}, "commit"=>"Create Expense duration"}