Add description of relevant database triggers to models
I'm using database triggers to handle some updates that are fairly related to data integrity or just otherwise seem to be most suitable as a trigger (such as updating the
num_comments counter for a topic automatically when comments are inserted, instead of needing to do it in the app code).
However, from a code perspective this can be confusing - some logic/updates happen automatically, but it's not visible in the Python code, and adds another place that people need to know to look at to fully understand what's happening. To improve this, a description of all triggers should be added to the relevant models somehow, maybe just inside their docstring. These descriptions should be fairly specific, and ideally make sure to state the column(s) that they effect, so that they'll come up if someone searches.