Stripe Integration with Parse - objective-c

Question

I have an ios/Objective C app. I'm using Parse. It's hosted on Heroku.
I'm attempting to integrate Stripe. I have installed the latest Stripe pod and am trying to follow the basic Standard Integration. https://stripe.com/docs/mobile/ios/standard
I'm getting tripped up by the steps involved with "Prepare Your API" and I'm unsure how to use the code provided "To provide an ephemeral key to the SDK, you'll need to expose a new API endpoint on your backend. This endpoint should create an ephemeral key for the current Stripe customer, and return the key's unmodified response as JSON" ...
All the Q&A I can find on how to use stripe with parse seem to predate the use of the ephemeral key and need to create this endpoint. Could you please provide me with more specific information about where the example code you provide (see below) for this goes? Is this something I need to do within the parse dashboard? Heroku? is this part of parse cloud? I vaguely recall from previous times I've played with parse apps several years ago, that there may be a main.js file (or similar) that can be incorporated into the app, but I don't recall where it goes or how to do it.
# Sinatra
post path do
stripe_version = params['api_version']
customer_id = session['customer_id']
key = Stripe::EphemeralKey.create(
{customer: customer_id},
{stripe_version: stripe_version}
)
key.to_json
end
If anyone has recently integrated stripe with a parse app I'd really appreciate guidance on how to do this.
Thanks!