Basic donation records

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

db/schema.rb

@@ -10,7 +10,18 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2020_11_30_132533) do
+ActiveRecord::Schema.define(version: 2020_12_17_161544) do
+
+  create_table "donations", force: :cascade do |t|
+    t.integer "user_id"
+    t.integer "amount_sats"
+    t.integer "amount_eur"
+    t.integer "amount_usd"
+    t.string "public_name"
+    t.datetime "created_at", precision: 6, null: false
+    t.datetime "updated_at", precision: 6, null: false
+    t.index ["user_id"], name: "index_donations_on_user_id"
+  end
 
   create_table "invitations", force: :cascade do |t|
     t.string "token"