authorize(
  params :: [
    scope: String.t(),
    against: %{
      optional(:client) => %Boruta.Oauth.Client{
        authorize_scope: term(),
        authorized_scopes: term(),
        id: term(),
        redirect_uris: term(),
        secret: term(),
        supported_grant_types: term()
      },
      optional(:resource_owner) => %Boruta.Accounts.User{
        __meta__: term(),
        authorized_scopes: term(),
        current_password: term(),
        email: term(),
        email_confirmation_token: term(),
        email_confirmed_at: term(),
        id: term(),
        inserted_at: term(),
        name: term(),
        password: term(),
        password_hash: term(),
        unconfirmed_email: term(),
        updated_at: term()
      },
      optional(:token) => %Boruta.Oauth.Token{
        client: term(),
        expires_at: term(),
        id: term(),
        inserted_at: term(),
        redirect_uri: term(),
        refresh_token: term(),
        resource_owner: term(),
        revoked_at: term(),
        scope: term(),
        state: term(),
        type: term(),
        value: term()
      }
    }
  ]
) :: {:ok, scope :: String.t()} | {:error, Boruta.Oauth.Error.t()}