Exclude `untracked_files_for_uploads` from schema

Because it is a temporary table meant only to facilitate a migration of data. It is referenced only by the post-deploy migration and 2 related background migrations.

It should be dropped when the data migration is finished.

db/schema.rb

@@ -1719,16 +1719,6 @@ ActiveRecord::Schema.define(version: 20171124150326) do
   add_index "u2f_registrations", ["key_handle"], name: "index_u2f_registrations_on_key_handle", using: :btree
   add_index "u2f_registrations", ["user_id"], name: "index_u2f_registrations_on_user_id", using: :btree
 
-  create_table "untracked_files_for_uploads", force: :cascade do |t|
-    t.string "path", null: false
-    t.boolean "tracked", default: false, null: false
-    t.datetime_with_timezone "created_at", null: false
-    t.datetime_with_timezone "updated_at", null: false
-  end
-
-  add_index "untracked_files_for_uploads", ["path"], name: "index_untracked_files_for_uploads_on_path", unique: true, using: :btree
-  add_index "untracked_files_for_uploads", ["tracked"], name: "index_untracked_files_for_uploads_on_tracked", using: :btree
-
   create_table "uploads", force: :cascade do |t|
     t.integer "size", limit: 8, null: false
     t.string "path", null: false