Write effective tests that check for webhook calls

[leemcd56]

Is your feature request related to a problem? Please describe.
Before deploying, each endpoint needs to be thoroughly tested.

Describe the solution you'd like
Add feature tests for /webhook, and unit tests for Event and Dispatcher classes.

[leemcd56]

Following up on this, there is a test I wrote to check if /webhook was correctly dispatching events but I was getting an HTTP 500 response from supertest.

[leemcd56]

@LeWestopher when you get the chance, can you look into what's causing these issues?