diff --git a/Gemfile b/Gemfile
index d2d6db90655bb8a99203aa962372b8a3bfd2f10e..71548920867421a6a1e6062fa859a7d1665ff6e9 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,7 +1,14 @@
 source "https://rubygems.org"
 
+git_source(:github) { |repo_path| "https://github.com/#{repo_path}.git" }
+
 gemspec
 
+gem "activesupport", github: "rails/rails"
+gem "activerecord", github: "rails/rails"
+gem "actionpack", github: "rails/rails"
+gem "activejob", github: "rails/rails"
+
 gem "rake"
 gem "byebug"
 
diff --git a/Gemfile.lock b/Gemfile.lock
index cce1d346dab6ef7874fa09f35810108b7b3cc863..eb8c229a4172f5eadc0b89102bdf73514577c433 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,42 +1,47 @@
-PATH
-  remote: .
-  specs:
-    activestorage (0.1)
-      actionpack (>= 5.1)
-      activejob (>= 5.1)
-      activerecord (>= 5.1)
-      activesupport (>= 5.1)
-
-GEM
-  remote: https://rubygems.org/
+GIT
+  remote: https://github.com/rails/rails.git
+  revision: c1f9fa8c69590222fac43d58bf64ef4a1225d7ce
   specs:
-    actionpack (5.1.1)
-      actionview (= 5.1.1)
-      activesupport (= 5.1.1)
+    actionpack (5.2.0.alpha)
+      actionview (= 5.2.0.alpha)
+      activesupport (= 5.2.0.alpha)
       rack (~> 2.0)
       rack-test (~> 0.6.3)
       rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.0.2)
-    actionview (5.1.1)
-      activesupport (= 5.1.1)
+    actionview (5.2.0.alpha)
+      activesupport (= 5.2.0.alpha)
       builder (~> 3.1)
       erubi (~> 1.4)
       rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.0.3)
-    activejob (5.1.1)
-      activesupport (= 5.1.1)
+    activejob (5.2.0.alpha)
+      activesupport (= 5.2.0.alpha)
       globalid (>= 0.3.6)
-    activemodel (5.1.1)
-      activesupport (= 5.1.1)
-    activerecord (5.1.1)
-      activemodel (= 5.1.1)
-      activesupport (= 5.1.1)
+    activemodel (5.2.0.alpha)
+      activesupport (= 5.2.0.alpha)
+    activerecord (5.2.0.alpha)
+      activemodel (= 5.2.0.alpha)
+      activesupport (= 5.2.0.alpha)
       arel (~> 8.0)
-    activesupport (5.1.1)
+    activesupport (5.2.0.alpha)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (~> 0.7)
       minitest (~> 5.1)
       tzinfo (~> 1.1)
+
+PATH
+  remote: .
+  specs:
+    activestorage (0.1)
+      actionpack (>= 5.2.0.alpha)
+      activejob (>= 5.2.0.alpha)
+      activerecord (>= 5.2.0.alpha)
+      activesupport (>= 5.2.0.alpha)
+
+GEM
+  remote: https://rubygems.org/
+  specs:
     addressable (2.5.1)
       public_suffix (~> 2.0, >= 2.0.2)
     arel (8.0.0)
@@ -55,7 +60,7 @@ GEM
     declarative (0.0.9)
     declarative-option (0.1.0)
     digest-crc (0.4.1)
-    erubi (1.6.0)
+    erubi (1.6.1)
     faraday (0.12.1)
       multipart-post (>= 1.2, < 3)
     globalid (0.4.0)
@@ -87,7 +92,7 @@ GEM
     httparty (0.15.5)
       multi_xml (>= 0.5.2)
     httpclient (2.8.3)
-    i18n (0.8.4)
+    i18n (0.8.6)
     jmespath (1.3.1)
     jwt (1.5.6)
     little-plugger (1.1.4)
@@ -100,13 +105,13 @@ GEM
     mime-types (3.1)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2016.0521)
-    mini_portile2 (2.1.0)
+    mini_portile2 (2.2.0)
     minitest (5.10.2)
     multi_json (1.12.1)
     multi_xml (0.6.0)
     multipart-post (2.0.0)
-    nokogiri (1.7.2)
-      mini_portile2 (~> 2.1.0)
+    nokogiri (1.8.0)
+      mini_portile2 (~> 2.2.0)
     os (0.9.6)
     parallel (1.11.2)
     parser (2.4.0.0)
@@ -153,7 +158,11 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
+  actionpack!
+  activejob!
+  activerecord!
   activestorage!
+  activesupport!
   aws-sdk (~> 2)
   bundler (~> 1.15)
   byebug
diff --git a/activestorage.gemspec b/activestorage.gemspec
index ce366d60c210ff1f7ebdadf87e3f95d4c5dfd3e1..884d3287e6763830966ea4366f632331df3bfb41 100644
--- a/activestorage.gemspec
+++ b/activestorage.gemspec
@@ -9,13 +9,13 @@
 
   s.required_ruby_version = ">= 2.3.0"
 
-  s.add_dependency "activesupport", ">= 5.1"
-  s.add_dependency "activerecord", ">= 5.1"
-  s.add_dependency "actionpack", ">= 5.1"
-  s.add_dependency "activejob", ">= 5.1"
+  s.add_dependency "activesupport", ">= 5.2.0.alpha"
+  s.add_dependency "activerecord", ">= 5.2.0.alpha"
+  s.add_dependency "actionpack", ">= 5.2.0.alpha"
+  s.add_dependency "activejob", ">= 5.2.0.alpha"
 
   s.add_development_dependency "bundler", "~> 1.15"
 
-  s.files         = `git ls-files`.split("\n")
-  s.test_files    = `git ls-files -- test/*`.split("\n")
+  s.files      = `git ls-files`.split("\n")
+  s.test_files = `git ls-files -- test/*`.split("\n")
 end