Developer docs

Backends

Sql Backend	How to implement translations for a new SQL dialect, or extend the SQL backend.
Pandas Backend	How the pandas backend implements fast grouped operations.

Core

Sql Translators	A closer look at the translation process, focused on SQL and the CallTreeLocal tree listener.
Call Trees	Calls represent “what” operations users want to do. This document describes how they are constructed, transformed, and executed.
Fast Pandas Grouped Ops	Why are grouped operations cumbersome? How does siuba simplify them?