Thredded is a Rails 4.2+ forum/messageboard engine. Its goal is to be as simple and feature rich as possible. Thredded works with SQLite, MySQL (v5.6.4+), and PostgreSQL. Thredded has no infrastructure dependencies other than the database and, if configured in the parent application, the ActiveJob backend dependency such as Redis. Currently only MRI Ruby 2.2+ is supported. We would love to support JRuby and Rubinius as well.