webhook: Javascript example does not explain creating webhooks

[sanjaybaskaran01]

Even though it is mentioned in the README the index.js does not explain how to create a webhook,

Possible addition:

1. Route to create webhooks and manage webhooks.
2. All of these webhooks IDs and secrets must be stored in a database ( instructions can be commented )

An improvement on how to create a webhook and store its secret would be nice