be more specific about csrf token and ajax - not whitelisted outside of jquery-rails [ci skip]
pass `habtm :autosave` to underlying `hm:t` association. Closes #13923.
some wording format changes. [ci skip]
docs, be clear that `options` is a hash. Closes #11904. [ci skip].
Merge pull request #11770 from timruffles/doc_ajax_xhr

be more specific about csrf token and ajax - not whitelisted outside of jquery-rails [ci skip]