adv_app.py: Use 'db-namespace' style approach

[pydanny]

---

name: Pull Request
about: Propose changes to the codebase
title: '[PR] Use 'db-namespace' style approach'
labels: 'cleanup,documentation'
assignees: 'pydanny'

---

Proposed Changes

We have seen people use attachment of tables to the database object as a way to have a 'namespace'. This way we can have db.todos represent the table and todos as a variable or function without collision.

While use of db.t for introspection is useful to know, this is documented in fastlite here.

Types of changes
What types of changes does your code introduce? Put an x in all the boxes that apply:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist
Go over all the following points, and put an x in all the boxes that apply:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.
• I am aware that this is an nbdev project, and I have edited, cleaned, and synced the source notebooks instead of editing .py or .md files directly.