diff --git a/README.adoc b/README.adoc
index 1efb5d7..2dfab8e 100644
--- a/README.adoc
+++ b/README.adoc
@@ -11,10 +11,6 @@ image:https://img.shields.io/codeclimate/maintainability/riboseinc/rails-keyserv
 
 A generic Rails engine for serving most kinds of keys.
 
-== Usage
-
-How to use my plugin.
-
 == Installation
 
 Add this line to your application’s Gemfile:
@@ -105,6 +101,27 @@ endpoints:
 }
 ----
 
+== Usage
+
+=== Override controllers and rendering methods
+
+==== Keys Controller
+
+* `#render_index`
+** `@composed` is the collection to render
+* `#render_show_json(key)`
+* `#render_show_ext(key)`
+
+==== Default settings for mounted routes
+
+[source,ruby]
+----
+# E.g. in config/routes.rb
+mount_keyserver at: 'ks', controllers: {
+  keys: 'rails/keyserver/api/v1/keys',
+}
+----
+
 == Contributing
 
 First, thank you for contributing! We love pull requests from everyone.
diff --git a/app/controllers/rails/keyserver/api/v1/keys_controller.rb b/app/controllers/rails/keyserver/api/v1/keys_controller.rb
index fdd431b..022f113 100644
--- a/app/controllers/rails/keyserver/api/v1/keys_controller.rb
+++ b/app/controllers/rails/keyserver/api/v1/keys_controller.rb
@@ -23,7 +23,7 @@ def set_composed
           end
 
           def index
-            render json: @composed.all
+            render_index
           end
 
           def show
@@ -40,17 +40,31 @@ def show
 
             respond_to do |format|
               format.json do
-                render json: key
+                render_show_json(key)
               end
 
               # If .pub requested, send key.public as an attachment.
               format.send(RK::Key::PGP.extension) do
-                render_options = {}
-                render_options[:"#{RK::Key::PGP.extension}"] = key
-                render render_options
+                render_show_ext(key)
               end
             end
           end
+
+          protected
+
+          def render_index
+            render json: @composed.all
+          end
+
+          def render_show_json(key)
+            render json: key
+          end
+
+          def render_show_ext(key)
+            render_options = {}
+            render_options[:"#{RK::Key::PGP.extension}"] = key
+            render render_options
+          end
         end
       end
     end