Automatic strong parameters detection

README.md

@@ -239,8 +239,11 @@ p[:occupation] # => 'Rubyist'
 ```
 
 ### Mash and Rails 4 Strong Parameters
+When using Mash with [Rails 4 Strong Parameters](http://edgeguides.rubyonrails.org/action_controller_overview.html#strong-parameters) Mash will automatically detect presence of strong parameters.
+**No further action is required.**
 
-Add the following initializer in config/initializers/mash.rb when using Mash with [Rails 4 Strong Parameters](http://edgeguides.rubyonrails.org/action_controller_overview.html#strong-parameters). This prevents Mash from responding to `:permitted?` and therefore triggering an ActiveModel `ForbiddenAttributesProtection` exception.
+However, If strong parameters can't be detected automatically try to include extension manually:
+Add the following initializer in config/initializers/mash.rb. This prevents Mash from responding to `:permitted?` and therefore triggering an ActiveModel `ForbiddenAttributesProtection` exception.
 
 ```ruby
 class Mash

hashie.gemspec

@@ -17,4 +17,5 @@ Gem::Specification.new do |gem|
 
   gem.add_development_dependency 'rake'
   gem.add_development_dependency 'rspec'
+  gem.add_development_dependency 'actionpack'
 end

lib/hashie/mash.rb

@@ -56,8 +56,9 @@ module Hashie
   #
   class Mash < Hash
     include Hashie::Extensions::PrettyInspect
+    include Hashie::Extensions::Mash::ActiveModel if defined?(ActionController::StrongParameters)
 
-    ALLOWED_SUFFIXES = %w(? ! = _)
+    ALLOWED_SUFFIXES = %w(? ! = _) unless defined?(ALLOWED_SUFFIXES)
 
     alias_method :to_s, :inspect
 

spec/hashie/mash_spec.rb

@@ -486,4 +486,16 @@ class SubMash < Hashie::Mash
       expect(hash).to eq Hashie::Hash['a' => 'hey', '123' => { '345' => 'hey' }]
     end
   end
+
+  describe 'it includes active model extensions' do
+    it 'includes active model extensions for strong parameters' do
+      require 'action_controller'
+      load 'hashie/mash.rb'
+      Hashie::Mash.included_modules.should include(Hashie::Extensions::Mash::ActiveModel)
+    end
+    it 'does not include active model extensions for strong parameters' do
+      load 'hashie/mash.rb'
+      Hashie::Mash.included_modules.should_not include(Hashie::Extensions::Mash::ActiveModel)
+    end
+  end
 end