additionist

Noun

 * 1)  One who supports or implements a policy of adding something.
 * 2) * Jeff Riggenbach, Why American History Is Not What They Say (page 85)
 * He was, he said, an "additionist"— the fellow who comes along after the historical accounts have been written and adds what's been (inadvertently or deliberately) left out.
 * He was, he said, an "additionist"— the fellow who comes along after the historical accounts have been written and adds what's been (inadvertently or deliberately) left out.