Uploads for admin site settings (#4913)

* Improve OpenGraph tags for about pages

* Add thumbnail admin setting

* Fix error

* Fix up

db/migrate/20170913000752_create_site_uploads.rb

@@ -0,0 +1,10 @@
+class CreateSiteUploads < ActiveRecord::Migration[5.1]
+  def change
+    create_table :site_uploads do |t|
+      t.string :var, default: '', null: false, index: { unique: true }
+      t.attachment :file
+      t.json :meta
+      t.timestamps
+    end
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20170905165803) do
+ActiveRecord::Schema.define(version: 20170913000752) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -288,6 +288,18 @@ ActiveRecord::Schema.define(version: 20170905165803) do
     t.index ["thing_type", "thing_id", "var"], name: "index_settings_on_thing_type_and_thing_id_and_var", unique: true
   end
 
+  create_table "site_uploads", force: :cascade do |t|
+    t.string "var", default: "", null: false
+    t.string "file_file_name"
+    t.string "file_content_type"
+    t.integer "file_file_size"
+    t.datetime "file_updated_at"
+    t.json "meta"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["var"], name: "index_site_uploads_on_var", unique: true
+  end
+
   create_table "status_pins", force: :cascade do |t|
     t.bigint "account_id", null: false
     t.bigint "status_id", null: false