You can do full-text search on Heroku FOR FREE by working around bogons in PgSearch's pg_search_scopes.

Two bogons I've encountered so far:

• To make them not require something to search on, wrap them in normal scopes that detect arg presence, and just don't call the pgsearchscope unless an arg was given.

• To chain two or more of them in one query, use .reorder to replace, not just add onto (as .order does), the sorting order.

Slides are at http://www.slideshare.net/dare2xl/full-text-search-on-heroku-for-free.