Document Suggested Method: Prisma Integration Testing Does Not Wait For the Testing Database in Docker

[kwan19961217]

Discussed in prisma/prisma#19245

So I have found out that the official document and the blog post related to this is not consistent:

1. Official Document's script does not work as the it cannot connect to the database
2. Blog post's suggested method add a part to check the database's readiness. However, it does not do it correctly and actually wait 15 seconds, therefore the test is able to run because the database is always ready after the timeout.

I have found out a solution after some digging and posted it on the original discussion.
I am wondering if the official document should be updated on the related section?