Support mount-specific swagger_root and add swagger_filter setting

spec/dummy/config/initializers/swagger_rails.rb

@@ -1,16 +1,14 @@
 SwaggerRails.configure do |c|
 
-  # Define your swagger documents and provide any global metadata here
-  # (Individual operations are generated from your spec/test files)
-  c.swagger_doc 'v1/swagger.json',
-    {
-      swagger: '2.0',
-      info: {
-        title: 'API V1',
-        version: 'v1'
-      }
-    }
+  # Specify a root folder where Swagger JSON files are located
+  # This is used by the Swagger middleware to serve requests for API descriptions
+  # NOTE: If you're using the rspec DSL to generate Swagger, you'll need to ensure
+  # that the same folder is also specified in spec/swagger_helper.rb
+  c.swagger_root = Rails.root.to_s + '/swagger'
 
-  # Specify a location to output generated swagger files
-  c.swagger_dir File.expand_path('../../../swagger', __FILE__)
+  # Inject a lamda function to alter the returned Swagger prior to serialization
+  # The function will have access to the rack env for the current request
+  # For example, you could leverage this to dynamically assign the "host" property
+  #
+  #c.swagger_filter = lambda { |swagger, env| swagger['host'] = env['HTTP_HOST'] }
 end