qb_akkoma/priv/repo/migrations/20181214121049_add_bookmarks_to_users.exs

defmodule Pleroma.Repo.Migrations.AddBookmarksToUsers do
  use Ecto.Migration

  def change do
    alter table(:users) do
      add :bookmarks, {:array, :string}, null: false, default: []
    end
  end
end