Upgrade to latest Rails, which apparently improves ActionCable performance

Gemfile

@@ -2,7 +2,7 @@
 
 source 'https://rubygems.org'
 
-gem 'rails', '5.0.0.1'
+gem 'rails', git: 'https://github.com/rails/rails.git', branch: '5-0-stable'
 gem 'sass-rails', '~> 5.0'
 gem 'uglifier', '>= 1.3.0'
 gem 'coffee-rails', '~> 4.1.0'

Gemfile.lock

@@ -1,5 +1,7 @@
-GEM
-  remote: https://rubygems.org/
+GIT
+  remote: https://github.com/rails/rails.git
+  revision: ecb394a31420f6fd1d0ab692c79f2dd44176e2c9
+  branch: 5-0-stable
   specs:
     actioncable (5.0.0.1)
       actionpack (= 5.0.0.1)
@@ -24,7 +26,6 @@ GEM
       erubis (~> 2.7.0)
       rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.0.2)
-    active_record_query_trace (1.5.3)
     activejob (5.0.0.1)
       activesupport (= 5.0.0.1)
       globalid (>= 0.3.6)
@@ -39,8 +40,31 @@ GEM
       i18n (~> 0.7)
       minitest (~> 5.1)
       tzinfo (~> 1.1)
+    rails (5.0.0.1)
+      actioncable (= 5.0.0.1)
+      actionmailer (= 5.0.0.1)
+      actionpack (= 5.0.0.1)
+      actionview (= 5.0.0.1)
+      activejob (= 5.0.0.1)
+      activemodel (= 5.0.0.1)
+      activerecord (= 5.0.0.1)
+      activesupport (= 5.0.0.1)
+      bundler (>= 1.3.0, < 2.0)
+      railties (= 5.0.0.1)
+      sprockets-rails (>= 2.0.0)
+    railties (5.0.0.1)
+      actionpack (= 5.0.0.1)
+      activesupport (= 5.0.0.1)
+      method_source
+      rake (>= 0.8.7)
+      thor (>= 0.18.1, < 2.0)
+
+GEM
+  remote: https://rubygems.org/
+  specs:
+    active_record_query_trace (1.5.3)
     addressable (2.4.0)
-    arel (7.1.1)
+    arel (7.1.4)
     ast (2.3.0)
     autoprefixer-rails (6.5.0.2)
       execjs
@@ -242,18 +266,6 @@ GEM
       rack
     rack-test (0.6.3)
       rack (>= 1.0)
-    rails (5.0.0.1)
-      actioncable (= 5.0.0.1)
-      actionmailer (= 5.0.0.1)
-      actionpack (= 5.0.0.1)
-      actionview (= 5.0.0.1)
-      activejob (= 5.0.0.1)
-      activemodel (= 5.0.0.1)
-      activerecord (= 5.0.0.1)
-      activesupport (= 5.0.0.1)
-      bundler (>= 1.3.0, < 2.0)
-      railties (= 5.0.0.1)
-      sprockets-rails (>= 2.0.0)
     rails-dom-testing (2.0.1)
       activesupport (>= 4.2.0, < 6.0)
       nokogiri (~> 1.6.0)
@@ -266,12 +278,6 @@ GEM
       rails (> 3.1)
     rails_serve_static_assets (0.0.5)
     rails_stdout_logging (0.0.5)
-    railties (5.0.0.1)
-      actionpack (= 5.0.0.1)
-      activesupport (= 5.0.0.1)
-      method_source
-      rake (>= 0.8.7)
-      thor (>= 0.18.1, < 2.0)
     rainbow (2.1.0)
     rake (11.3.0)
     rdoc (4.2.2)
@@ -362,7 +368,7 @@ GEM
     sprockets (3.7.0)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
-    sprockets-rails (3.1.1)
+    sprockets-rails (3.2.0)
       actionpack (>= 4.0)
       activesupport (>= 4.0)
       sprockets (>= 3.0.0)
@@ -443,7 +449,7 @@ DEPENDENCIES
   rabl
   rack-attack
   rack-cors
-  rails (= 5.0.0.1)
+  rails!
   rails_12factor
   rails_autolink
   react-rails