Stripe Gateway on Active Merchant not working

I was working to make payments through Stripe Gateway through Active Merchant gem on a Rails 4 application.

I came along this script and made a similar script by also watching some other resources as follows:

require 'active_merchant'

# Use the TrustCommerce test servers
ActiveMerchant::Billing::Base.mode = :test

gateway = ActiveMerchant::Billing::StripeGateway.new(:login => Rails.application.secrets.stripe_secret_key)

# ActiveMerchant accepts all amounts as Integer values in cents
amount = 1000  # $10.00

# The card verification value is also known as CVV2, CVC2, or CID
credit_card = ActiveMerchant::Billing::CreditCard.new(
                :first_name         => 'Bob',
                :last_name          => 'Bobsen',
                :number             => '4242424242424242',
                :month              => '8',
                :year               => Time.now.year+1,
                :verification_value => '000')

purchase_options = {
      :ip => "127.0.0.1",
      :billing_address => {
        :name     => "Ryan Bates",
        :address1 => "123 Main St.",
        :city     => "New York",
        :state    => "NY",
        :country  => "US",
        :zip      => "10001"
      }
    }

# Validating the card automatically detects the card type
if credit_card.validate.empty?
  # Capture $10 from the credit card
  response = gateway.purchase(amount, credit_card, purchase_options)

  if response.success?
    puts "Successfully charged $#{sprintf("%.2f", amount / 100)} to the credit card #{credit_card.display_number}"
  else
    raise StandardError, response.message
  end
end

but this script generates an error with the following error log:

/Library/Ruby/Gems/2.0.0/gems/activemerchant-1.58.0/lib/active_merchant/billing/gateways/stripe.rb:469:in `rescue in api_request': uninitialized constant ActiveMerchant::Billing::StripeGateway::JSON (NameError)
        from /Library/Ruby/Gems/2.0.0/gems/activemerchant-1.58.0/lib/active_merchant/billing/gateways/stripe.rb:463:in `api_request'
        from /Library/Ruby/Gems/2.0.0/gems/activemerchant-1.58.0/lib/active_merchant/billing/gateways/stripe.rb:477:in `commit'
        from /Library/Ruby/Gems/2.0.0/gems/activemerchant-1.58.0/lib/active_merchant/billing/gateways/stripe.rb:100:in `block (2 levels) in purchase'
        from /Library/Ruby/Gems/2.0.0/gems/activemerchant-1.58.0/lib/active_merchant/billing/response.rb:59:in `process'
        from /Library/Ruby/Gems/2.0.0/gems/activemerchant-1.58.0/lib/active_merchant/billing/gateways/stripe.rb:98:in `block in purchase'
        from /Library/Ruby/Gems/2.0.0/gems/activemerchant-1.58.0/lib/active_merchant/billing/response.rb:45:in `tap'
        from /Library/Ruby/Gems/2.0.0/gems/activemerchant-1.58.0/lib/active_merchant/billing/response.rb:45:in `run'
        from /Library/Ruby/Gems/2.0.0/gems/activemerchant-1.58.0/lib/active_merchant/billing/gateways/stripe.rb:93:in `purchase'
        from stripe.rb:35:in `<main>'

Can you suggest a workaround for this error?

so it looks like a simple workaround as suggested by @bkunzi01

i thought that active merchant already used stripe in its ActiveMerchant::Billing::StripeGateway file but it doesn't.

just included require 'stripe' at the top of the script and transaction was successful :)