Issuable-like Rails models utilities

GitLab Rails codebase contains several models that hold common functionality and behave similarly to Issues. Other examples of "issuables" are merge requests and Epics.

This guide accumulates guidelines on working with such Rails models.

Important text fields

There are maximum length constraints for the most important text fields for issuables:

• title: 255 characters
• title_html: 800 characters
• description: 1 megabyte
• description_html: 5 megabytes