Documentation mismatch

[AlexanderKachechka]

Problem/Motivation

Seems like you have a documentation mismatch.
In the GitHub description you can find that access_code should be retrieved from the backend and provided via Charge object.

App prompts your backend to initialize a transaction
Your backend returns access_code we return when it calls the [Initialize Transaction](https://paystack.com/docs/api/#transaction-initialize) endpoint
App provides the access_code and card details to our SDK's chargeCard function via Charge object

But in the documentation from website there is no requirements for access_code
https://paystack.com/docs/guides/accept_payments_on_your_android_app/

And charge from the card (at least test card) can be processed without providing access_code.

Proposed resolution

• Update GitHub description to be more consistent with documentation from the website.
• Provide additional description for the access_code usage.