Due to the use of the dataclasses mixin on the SQLAlchemy types, a
back_populates creates a RecursiveError when comparing two types. This
occurs because the dataclass will overwrite the __eq__ operator, and it
doesn't know when to stop comparing relationships.
Removing the dataclasses isn't the best approach, since then __init__,
__eq__ and __repr__ methods would have to be added to all types. Thus
the solution was to remove the relationship on the child (on a
one-to-one relationship) from the __eq__ operation, with the use of the
compare parameter.
Took the opportunity to define more logical __init__ methods on the
`Rule` and child classes.
Also revised the parameter options on some DB types.
Swap almost all remaining calls to the old postgresql only DB class with
the new DB client.
Warning! Some operations are currently not implement, such as setting
category schedules and dismantling links.
`update` and `delete` methods added to DB `Client`.
For DB connections that want to keep a session alive, there's a new
`DatabaseSession` class that holds a SQLAlchemy session inside and
offers methods similar to the `Database` class.
The `Database` moves to use the `DatabaseSession` to remove duplicated
code.
The database `Client` wasn't working correcly when no session was
passed, as the inserted transactions would still be bound to the newly
created session inside.
Creates a copy of the input transactions to insert on the DB.
`add` method replaced with `insert`.
`insert` and `select` implemented for new database base class.
Database unit test added.
Due to SQLite implementation of the primary key autoinc, the type of the
IDs on the database for SQLite changed to Integer.
https://www.sqlite.org/autoinc.html
