create_tables_on_startd created, docs added

[igorbenav]

Closes #84

If you want to stop tables from being created every time you run the api, you should disable this here:

# app/main.py

from .api import router
from .core.config import settings
from .core.setup import create_application

# create_tables_on_start defaults to True
app = create_application(router=router, settings=settings, create_tables_on_start=False)

This create_application function is defined in app/core/setup.py, and it's a flexible way to configure the behavior of your application.

A few examples:

• Deactivate or password protect /docs
• Add client-side cache middleware
• Add Startup and Shutdown event handlers for cache, queue and rate limit