pleroma/priv/repo/migrations/20220225164000_add_activity_assigned_account_index.exs

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

  def change do
    create_if_not_exists(
      index(:activities, ["(data->>'assigned_account')"],
        name: :activities_assigned_account_index
      )
    )
  end
end