Possible demo with token database access?

[JohnAD]

I like that the library does NOT have a database dependency, narrowly focusing on the proper handling of transactions instead.

However, it would be really nice if there were a real-world example or demo of it being used in the context of some kinds of DB or storage. It could be as simple as a SQLite backend. I can't imagine a real-world usage of this library without permanent storage. The demo would be showing an example of:

• serializing/saving a new transaction into a set of db tables
• reading from db tables into an accountant object and demonstrating the return of a balance, etc.

[JohnAD]

Or, I could create such a demo and send it in a PR. 😄