Please include a reference to the 'Related objects reference' in '/en/1.x/ref/models/fields/#manytomanyfield'

[jammon]

Maybe it's just me. But more than once I was seeking for the description of ManyToManyField.add() and didn't find it in '/en/1.2/ref/models/fields/#manytomanyfield', where all the arguments of ManyToManyField are described.

(Now I understood, that 'add()' is a method of RelatedManager and not of ManyToManyField. But for the uninitiated it looks as if you could add relations to a ManyToManyField through its add()-method - which might as well be intentional.)

Maybe add something like this to '/ref/models/fields/#manytomanyfield': "Related objects can be added, removed or created with the ManyToManyField's :doc:RelatedManager</ref/models/relations>."

[Aymeric Augustin]

Change UI/UX from NULL to False.

[Aymeric Augustin]

Change Easy pickings from NULL to False.

[Tim Graham <timograham@…>]

In 0fdfcee257155ad29ff161725d94f41f0e77691f:

Fixed #15325 - Added a link to RelatedManager in the ManytoManyField docs; thanks jammon for the suggestion.

[Tim Graham <timograham@…>]

In 1189dca471b9d2c01a570526fbbcddf659dfff43:

[1.4.X] Fixed #15325 - Added a link to RelatedManager in the ManytoManyField docs; thanks jammon for the suggestion.

Backport of 0fdfcee257 from master