select2 and Bootstrap not styling input field elements in rails - ruby-on-rails

Question

My input fields are not looking like they should, as per http://ivaynberg.github.io/select2/#documentation
Not only is the Bootstrap or select2 styling not applying to the input fields, I'm getting some funny duplicate behavior of the labels and forms here.
My unsubstantiated haunch is that Bootstrap isn't being properly registered or communicating with select2.
app/views/characters/_form.html.haml
= form_for(#character, :html => { :multipart => true }) do |f|
- if #character.errors.any?
#error_explanation
%h2= "#{pluralize(#character.errors.count, "error")} prohibited this character from being saved:"
%ul
- #character.errors.full_messages.each do |msg|
%li= msg
#stripe_error.alert.alert-danger{ :style => "display:none" }
%noscript JavaScript is not enabled and is required for this form. First enable it in your web browser settings.
.form-group
= f.label :name
= f.text_field :name, autofocus: true
.form-group
= f.label :image
= f.file_field :image
.form-group
= f.label :universe_ids, "Link Universes"
= f.collection_select :universe_ids, Universe.order(:name), :id, :name, {}, {multiple: true} # Getting a lot of funny behavior with these lines
.action
= f.submit
characters.js.coffee
jQuery ->
$("#character_universe_ids").select2(
placeholder: "Pick a Universe");
application.js
//= require jquery
//= require jquery.turbolinks
//= require jquery_ujs
//
//= require bootstrap
//= require select2
//
//= require_self
//= require_tree .
//= require turbolinks
application.css.scss
#import "resets";
#import "bootstrap";
#import "custom/cp_variables";
#import "custom/cp_custom";
#import "custom/cp_responsive";
/*
*= require select2
*= require select2-bootstrap
*
*= require_self
*= require_tree .
*/
How would I be able to tell if the *= select2-bootstrap line is working properly?
I am using bootstrap-sass gem, not a copied library in the vendor assets folder.
gemfile
source 'https://rubygems.org'
ruby "2.0.0"
gem 'rails', '4.0.0'
gem 'haml-rails', '0.5.1'
gem 'html2haml', '~> 1.0.1'
gem 'sass-rails', '~> 4.0.0'
gem 'autoprefixer-rails'
gem 'bootstrap-sass', '~> 3.1.1'
gem 'coffee-rails', '~> 4.0.0'
gem 'jquery-rails'
gem 'uglifier', '>= 1.3.0'
gem 'turbolinks', '~>2.2.2'
gem 'jquery-turbolinks', '~>2.0.2'
gem 'jbuilder', '~> 1.2'
gem 'sprockets-rails', :require => 'sprockets/railtie'
gem 'pg', '0.17.1'
group :doc do
# bundle exec rake doc:rails generates the API under doc/api.
gem 'sdoc', require: false
end
gem 'nokogiri', '~> 1.6.0'
# Secret keys.
gem 'figaro', '~> 0.7.0'
# Images.
gem 'paperclip', '~> 3.0'
# Image storage.
gem 'paperclip-dropbox', '>= 1.1.7'
# Authentication.
gem 'devise'#, '3.2.3'
# Votes.
gem 'acts_as_votable', '~> 0.9.0'
# Autocomplete form.
gem 'select2-rails'
group :development do
# For html2haml mass conversion
# erubis is already included in action pack
gem 'ruby_parser', '~> 3.1.1'
end
group :test do
end
group :production do
gem 'rails_12factor', '0.0.2'
#gem 'aws-sdk', "~> 1.0"
end
# Use ActiveModel has_secure_password
# gem 'bcrypt-ruby', '~> 3.0.0'
# Use unicorn as the app server
# gem 'unicorn'
# Use Capistrano for deployment
# gem 'capistrano', group: :development
# Use debugger
# gem 'debugger', group: [:development, :test]
I couldn't find any threads of people having this problem. All the tutorials simply say to apply the simple .select2() method to the proper DOM element, but I'm simply not getting the styling that I should be getting.