Basic donation records

Adds donation model/table and basic manual management in the admin
panel, as well as basic listing of users' own donations.

config/routes.rb

@@ -1,4 +1,5 @@
 Rails.application.routes.draw do
+  resources :donations
   devise_for :users
 
   get 'welcome', to: 'welcome#index'
@@ -16,6 +17,7 @@ Rails.application.routes.draw do
   namespace :admin do
     root to: 'dashboard#index'
     get 'ldap_users', to: 'ldap_users#index'
+    resources :donations
   end
 
   # Letter Opener (open "sent" emails in dev and staging)