Ruby on Rails
Komodo Edit

Komodo edit is an open source* code editor based on the commericial Komodo IDE. Although the IDE might be prohibitively expensive for some, Komodo Edit itself is free. It is similar to Textmate in many respects, including the project drawer, and (some) auto completion.

An excellent alternative for one who wants Textmate, but can’t afford it. Or someone seeking an Open Source editor with some IDE like functionality.