Adds .option method to Strategy for even more declarative configuration.

lib/omniauth/strategy.rb

@@ -51,6 +51,25 @@ module OmniAuth
         yield default_options and return unless options
         default_options.deep_merge!(options)
       end
+
+      # Directly declare a default option for your class. This is a useful from
+      # a documentation perspective as it provides a simple line-by-line analysis
+      # of the kinds of options your strategy provides by default.
+      #
+      # @param name [Symbol] The key of the default option in your configuration hash.
+      # @param value [Object] The value your object defaults to. Nil if not provided.
+      #
+      # @example
+      #
+      #   class MyStrategy
+      #     include OmniAuth::Strategy
+      #
+      #     option :foo, 'bar'
+      #     option 
+      #   end
+      def option(name, value = nil)
+        default_options[name] = value
+      end
     end
 
     # Initializes the strategy by passing in the Rack endpoint,

spec/omniauth/strategy_spec.rb

@@ -59,6 +59,18 @@ describe OmniAuth::Strategy do
     end
   end
 
+  describe '.option' do
+    subject { klass = Class.new; klass.send :include, OmniAuth::Strategy; klass }
+    it 'should set a default value' do
+      subject.option :abc, 123
+      subject.default_options.abc.should == 123
+    end
+
+    it 'should set the default value to nil if none is provided' do
+      subject.option :abc
+      subject.default_options.abc.should be_nil
+    end
+  end
 
   describe '#initialize' do
     context 'options extraction' do