Allow fetching special files in the documentation

spec/example_app/app/controllers/docs_controller.rb

@@ -1,19 +1,46 @@
 class DocsController < ApplicationController
+  SPECIAL_FILES = [
+    {
+      file: 'CONTRIBUTING',
+      page: 'contributing'
+    },
+    {
+      file: 'README',
+      page: 'index'
+    }
+  ].freeze
+
   REDCARPET_CONFIG = {
     fenced_code_blocks: true,
     autolink: true,
   }.freeze
 
-  def index
-    render_page "README"
+  def show
+    render_correct_page
   end
 
-  def show
-    render_page "docs/#{params[:page]}"
+  def find_special_file
+    params[:page].nil? ? retrieve_index_content : retrieve_everypage_content
   end
 
   private
 
+  def retrieve_index_content
+    SPECIAL_FILES.find { |page| page[:page] == 'index' }
+  end
+
+  def retrieve_everypage_content
+    SPECIAL_FILES.find { |page| page[:page] == params[:page] }
+  end
+
+  def render_correct_page
+    if find_special_file
+      render_page find_special_file[:file]
+    else
+      render_page "docs/#{params[:page]}"
+    end
+  end
+
   def render_page(name)
     path = full_page_path(name)
 

spec/example_app/config/routes.rb

@@ -19,5 +19,5 @@
   end
 
   get "/:page", to: "docs#show"
-  root to: "docs#index"
+  root to: 'docs#show'
 end