Remove redundant dependencies from Gemfile's

Gemfile

@@ -1,7 +1,3 @@
 source "https://rubygems.org"
 
 gemspec
-
-gem "activeresource", '~> 4.0.0'
-
-gem 'minitest', "~> 4.2"

Gemfile_ar40threadsafe

@@ -3,5 +3,3 @@ source "https://rubygems.org"
 gemspec
 
 gem 'activeresource', :git => 'git://github.com/Shopify/activeresource', tag: '4.0-threadsafe'
-
-gem 'minitest', "~> 4.2"

Gemfile_ar50

@@ -2,10 +2,4 @@ source "https://rubygems.org"
 
 gemspec
 
-gem 'activeresource', git: 'git://github.com/rails/activeresource', ref: 'c3cd2b535b7c5cdc12cc6a3c1e11be6c74ffa179'
-
-gem 'minitest', "~> 5.1"
-gem 'activesupport', github: 'rails/rails'
-gem 'activemodel', github: 'rails/rails'
-gem 'arel', github: 'rails/arel'
-gem 'rails-observers', github: 'rails/rails-observers'
+gem 'activeresource', git: 'git://github.com/rails/activeresource'