Attempt to yarnify as well

Gemfile

@@ -2,19 +2,18 @@
 source 'http://rubygems.org'
 source 'http://rails-assets.org'
 
-# These rails-assets dependencies need to be added to the developer's Gemfile
-# since there's no way to specify a source in the gemspec.
-source 'http://rails-assets.org' do
-  gem 'rails-assets-shepherd.js', '~> 1.8'
-  gem 'rails-assets-js-cookie', '~> 2.1'
-  gem 'rails-assets-tether', '~> 1.4'
-end
-
 # Declare your gem's dependencies in abraham.gemspec.
 # Bundler will treat runtime dependencies like base dependencies, and
 # development dependencies will be added by default to the :development group.
 gemspec
 
+
+source 'http://rails-assets.org' do
+  gem 'rails-assets-shepherd.js', '~> 1.8'
+  gem 'rails-assets-js-cookie', '~> 2.1'
+  gem 'rails-assets-tether', '~> 1.4'
+end
+
 # Declare any dependencies that are still in development here instead of in
 # your gemspec. These might include edge Rails or gems from your path or
 # Git. Remember to move these dependencies to your gemspec before releasing

abraham.gemspec

@@ -20,9 +20,6 @@ Gem::Specification.new do |s|
   s.add_dependency 'rails', '~> 5.0.0', '>= 5.0.0.1'
   s.add_dependency 'sass-rails', '~> 5.0'
   s.add_dependency 'jquery-rails'
-  s.add_dependency 'rails-assets-shepherd.js', '~> 1.8'
-  s.add_dependency 'rails-assets-js-cookie', '~> 2.1'
-  s.add_dependency 'rails-assets-tether', '~> 1.4'
 
   s.add_development_dependency 'sqlite3'
   s.add_development_dependency 'rubocop'

app/assets/javascripts/abraham/index.js

@@ -2,7 +2,7 @@
 //= require jquery_ujs
 //= require js-cookie
 //= require tether
-//= require shepherd.js.js
+//= require tether-shepherd
 
 $(document).on('turbolinks:before-cache', function() {
     // Remove visible product tours