Allow headers to be set inside an example.

Closes #86

lib/rspec_api_documentation/dsl/endpoint.rb

@@ -59,6 +59,11 @@ def params
       parameters
     end
 
+    def header(name, value)
+      example.metadata[:headers] ||= {}
+      example.metadata[:headers][name] = value
+    end
+
     def headers
       return unless example.metadata[:headers]
       example.metadata[:headers].inject({}) do |hash, (header, value)|

spec/dsl_spec.rb

@@ -400,6 +400,19 @@
       end
     end
 
+    put "/orders" do
+      context "setting header in example level" do
+        before do
+          header "Accept", "application/json"
+          header "Content-Type", "application/json"
+        end
+
+        it "adds to headers" do
+          headers.should == { "Accept" => "application/json", "Content-Type" => "application/json" }
+        end
+      end
+    end
+
     put "/orders" do
       header "Accept", :accept