You can also refer a tag file via `ctags`:
~/.ctags
--recurse
--totals
--extra=+f
--langdef=markdown
--langmap=markdown:+.md.mkd
--regex-markdown=/^#[ \t]+([0-9.]+[ \t]+)?(.*)/\2/h,Heading_L1/
--regex-markdown=/^##[ \t]+([0-9.]+[ \t]+)?(.*)/\2/i,Heading_L2/
--regex-markdown=/^###[ \t]+([0-9.]+[ \t]+)?(.*)/\2/k,Heading_L3/
