post '/account/external_account' do
  begin
    account = Stripe::Account.retrieve(params[:stripe_account])
    account.external_accounts.create(
      :object => "bank_account",
      :country => "US",
      :currency => "usd",
      :routing_number => "110000000",
      :account_number => "000123456789"
    )
  rescue Stripe::StripeError => e
    status 402
    return "Error adding external account to customer account: #{e.message}"
  end
  status 200
  return account.to_json
end