diff --git a/Gemfile.lock b/Gemfile.lock
index f297a86..77a240d 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -3,44 +3,51 @@ PATH
   specs:
     shopping (0.5.2)
       jsonapi-resources
-      rails (~> 4.2)
+      rails (>= 4.2)
 
 GEM
   remote: https://rubygems.org/
   specs:
-    actionmailer (4.2.8)
-      actionpack (= 4.2.8)
-      actionview (= 4.2.8)
-      activejob (= 4.2.8)
+    actioncable (5.2.3)
+      actionpack (= 5.2.3)
+      nio4r (~> 2.0)
+      websocket-driver (>= 0.6.1)
+    actionmailer (5.2.3)
+      actionpack (= 5.2.3)
+      actionview (= 5.2.3)
+      activejob (= 5.2.3)
       mail (~> 2.5, >= 2.5.4)
-      rails-dom-testing (~> 1.0, >= 1.0.5)
-    actionpack (4.2.8)
-      actionview (= 4.2.8)
-      activesupport (= 4.2.8)
-      rack (~> 1.6)
-      rack-test (~> 0.6.2)
-      rails-dom-testing (~> 1.0, >= 1.0.5)
+      rails-dom-testing (~> 2.0)
+    actionpack (5.2.3)
+      actionview (= 5.2.3)
+      activesupport (= 5.2.3)
+      rack (~> 2.0)
+      rack-test (>= 0.6.3)
+      rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.0.2)
-    actionview (4.2.8)
-      activesupport (= 4.2.8)
+    actionview (5.2.3)
+      activesupport (= 5.2.3)
       builder (~> 3.1)
-      erubis (~> 2.7.0)
-      rails-dom-testing (~> 1.0, >= 1.0.5)
+      erubi (~> 1.4)
+      rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.0.3)
-    activejob (4.2.8)
-      activesupport (= 4.2.8)
-      globalid (>= 0.3.0)
-    activemodel (4.2.8)
-      activesupport (= 4.2.8)
-      builder (~> 3.1)
-    activerecord (4.2.8)
-      activemodel (= 4.2.8)
-      activesupport (= 4.2.8)
-      arel (~> 6.0)
-    activesupport (4.2.8)
-      i18n (~> 0.7)
+    activejob (5.2.3)
+      activesupport (= 5.2.3)
+      globalid (>= 0.3.6)
+    activemodel (5.2.3)
+      activesupport (= 5.2.3)
+    activerecord (5.2.3)
+      activemodel (= 5.2.3)
+      activesupport (= 5.2.3)
+      arel (>= 9.0)
+    activestorage (5.2.3)
+      actionpack (= 5.2.3)
+      activerecord (= 5.2.3)
+      marcel (~> 0.3.1)
+    activesupport (5.2.3)
+      concurrent-ruby (~> 1.0, >= 1.0.2)
+      i18n (>= 0.7, < 2)
       minitest (~> 5.1)
-      thread_safe (~> 0.3, >= 0.3.4)
       tzinfo (~> 1.1)
     addressable (2.5.1)
       public_suffix (~> 2.0, >= 2.0.2)
@@ -48,7 +55,7 @@ GEM
       kramdown
       railties
       rspec_api_documentation
-    arel (6.0.4)
+    arel (9.0.0)
     builder (3.2.3)
     capybara (2.14.0)
       addressable
@@ -58,12 +65,12 @@ GEM
       rack-test (>= 0.5.4)
       xpath (~> 2.0)
     coderay (1.1.1)
-    concurrent-ruby (1.0.5)
-    crass (1.0.3)
+    concurrent-ruby (1.1.5)
+    crass (1.0.4)
     database_cleaner (1.6.1)
     diff-lcs (1.3)
     docile (1.1.5)
-    erubis (2.7.0)
+    erubi (1.8.0)
     factory_girl (4.8.0)
       activesupport (>= 3.0.0)
     factory_girl_rails (4.8.0)
@@ -71,63 +78,67 @@ GEM
       railties (>= 3.0.0)
     globalid (0.4.2)
       activesupport (>= 4.2.0)
-    i18n (0.9.1)
+    i18n (1.6.0)
       concurrent-ruby (~> 1.0)
     json (2.1.0)
-    jsonapi-resources (0.9.5)
+    jsonapi-resources (0.9.6)
       activerecord (>= 4.1)
       concurrent-ruby
       railties (>= 4.1)
     kramdown (1.13.2)
-    loofah (2.1.1)
+    loofah (2.2.3)
       crass (~> 1.0.2)
       nokogiri (>= 1.5.9)
     mail (2.7.1)
       mini_mime (>= 0.1.1)
+    marcel (0.3.3)
+      mimemagic (~> 0.3.2)
     method_source (0.8.2)
     mime-types (3.1)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2016.0521)
+    mimemagic (0.3.3)
     mini_mime (1.0.1)
-    mini_portile2 (2.3.0)
-    minitest (5.11.1)
+    mini_portile2 (2.4.0)
+    minitest (5.11.3)
     mustache (1.0.5)
-    nokogiri (1.8.2)
-      mini_portile2 (~> 2.3.0)
+    nio4r (2.3.1)
+    nokogiri (1.10.3)
+      mini_portile2 (~> 2.4.0)
     pg (0.20.0)
     pry (0.10.4)
       coderay (~> 1.1.0)
       method_source (~> 0.8.1)
       slop (~> 3.4)
     public_suffix (2.0.5)
-    rack (1.6.8)
-    rack-test (0.6.3)
-      rack (>= 1.0)
-    rails (4.2.8)
-      actionmailer (= 4.2.8)
-      actionpack (= 4.2.8)
-      actionview (= 4.2.8)
-      activejob (= 4.2.8)
-      activemodel (= 4.2.8)
-      activerecord (= 4.2.8)
-      activesupport (= 4.2.8)
-      bundler (>= 1.3.0, < 2.0)
-      railties (= 4.2.8)
-      sprockets-rails
-    rails-deprecated_sanitizer (1.0.3)
-      activesupport (>= 4.2.0.alpha)
-    rails-dom-testing (1.0.9)
-      activesupport (>= 4.2.0, < 5.0)
-      nokogiri (~> 1.6)
-      rails-deprecated_sanitizer (>= 1.0.1)
-    rails-html-sanitizer (1.0.3)
-      loofah (~> 2.0)
-    railties (4.2.8)
-      actionpack (= 4.2.8)
-      activesupport (= 4.2.8)
+    rack (2.0.7)
+    rack-test (1.1.0)
+      rack (>= 1.0, < 3)
+    rails (5.2.3)
+      actioncable (= 5.2.3)
+      actionmailer (= 5.2.3)
+      actionpack (= 5.2.3)
+      actionview (= 5.2.3)
+      activejob (= 5.2.3)
+      activemodel (= 5.2.3)
+      activerecord (= 5.2.3)
+      activestorage (= 5.2.3)
+      activesupport (= 5.2.3)
+      bundler (>= 1.3.0)
+      railties (= 5.2.3)
+      sprockets-rails (>= 2.0.0)
+    rails-dom-testing (2.0.3)
+      activesupport (>= 4.2.0)
+      nokogiri (>= 1.6)
+    rails-html-sanitizer (1.0.4)
+      loofah (~> 2.2, >= 2.2.2)
+    railties (5.2.3)
+      actionpack (= 5.2.3)
+      activesupport (= 5.2.3)
+      method_source
       rake (>= 0.8.7)
-      thor (>= 0.18.1, < 2.0)
-    rake (12.3.0)
+      thor (>= 0.19.0, < 2.0)
+    rake (12.3.2)
     rspec (3.6.0)
       rspec-core (~> 3.6.0)
       rspec-expectations (~> 3.6.0)
@@ -169,10 +180,13 @@ GEM
       activesupport (>= 4.0)
       sprockets (>= 3.0.0)
     sqlite3 (1.3.13)
-    thor (0.20.0)
+    thor (0.20.3)
     thread_safe (0.3.6)
-    tzinfo (1.2.4)
+    tzinfo (1.2.5)
       thread_safe (~> 0.1)
+    websocket-driver (0.7.0)
+      websocket-extensions (>= 0.1.0)
+    websocket-extensions (0.1.3)
     xpath (2.0.0)
       nokogiri (~> 1.3)
 
@@ -194,4 +208,4 @@ DEPENDENCIES
   sqlite3
 
 BUNDLED WITH
-   1.16.2
+   2.0.1
diff --git a/app/services/shopping/update_line_item_service.rb b/app/services/shopping/update_line_item_service.rb
index a814644..f0e8444 100644
--- a/app/services/shopping/update_line_item_service.rb
+++ b/app/services/shopping/update_line_item_service.rb
@@ -31,7 +31,7 @@ def perform!
     end
 
     def update!
-      line_item = @cart.line_items.find_by!(source_id: @source.id, source_type: @source.type, sale_price: @source.price)
+      line_item = @cart.line_items.find_by!(source_id: @source.id, source_type: @source.class.name, sale_price: @source.price)
       line_item.quantity = @quantity
       original_options = line_item.options || {}
       line_item.options = original_options.merge(options)
diff --git a/shopping.gemspec b/shopping.gemspec
index 729a0eb..acd7640 100644
--- a/shopping.gemspec
+++ b/shopping.gemspec
@@ -17,7 +17,7 @@ Gem::Specification.new do |s|
   s.files = Dir["{app,config,db,lib}/**/*", "MIT-LICENSE", "Rakefile", "README.rdoc"]
   s.test_files = Dir["test/**/*"]
 
-  s.add_dependency "rails", "~> 4.2"
+  s.add_dependency "rails", ">= 4.2"
   s.add_dependency "jsonapi-resources"
   # s.add_dependency 'doorkeeper', '4.2.5'