Add controller for rendering avatars on simple URL

config/routes.rb

@@ -15,6 +15,9 @@ Rails.application.routes.draw do
   match 'signup/:step', to: 'signup#steps', as: :signup_steps, via: [:get, :post]
   post 'signup_validate', to: 'signup#validate'
 
+
+  get "users/:username/avatars/:hash", to: "avatars#show", as: :user_avatar
+
   namespace :contributions do
     root to: 'donations#index'
     resources :donations, only: ['index', 'create'] do