# Issuable-like Rails models utilities

GitLab Rails codebase contains several models that hold common functionality and behave similarly to an [Issue]. Other
examples of `Issuable`s are [Merge Requests] and [Epics].

This guide accumulates guidelines on working with such Rails models.

## Important text fields

There are max length constraints for the most important text fields for `Issuable`s:

- `title`: 255 chars
- `title_html`: 800 chars
- `description`: 1 megabyte
- `description_html`: 5 megabytes

[Issue]: https://docs.gitlab.com/ee/user/project/issues
[Merge Requests]: https://docs.gitlab.com/ee/user/project/merge_requests
[Epics]: https://docs.gitlab.com/ee/user/group/epics