Added New function for GitIgnore struct.
Added New function for GitIgnore struct.

cmars/tools,syohex/the_platinum_searcher,cmars/tools,thomasf/the_platinum_searcher,DaSea/the_platinum_searcher,tw4452852/the_platinum_searcher,monochromegane/the_platinum_searcher,cmars/tools,cmars/tools,aeruder/the_platinum_searcher,yuya-takeyama/the_platinum_searcher