Documentation for development

Warning

TODO: This document is a work in progress. Please help us improve it!

See those other useful documents as well:

knowledge.md for high-level architecture and design decisions.
README.md for the backend API
README.md for the email routines and how to set up a local server for quick email rendering
README.md for the frontend / web server
testing.md for testing guidance and direction
database-schema.md for database schema and migrations
performance-optimization.md for performance best practices
database-connection-pooling.md for database connection management
troubleshooting.md for resolving common development issues
profile-fields.md for adding new profile fields
internationalization.md for adding new languages