feat(merge_chapters.sh): add merge_chapters.sh
feat(merge_chapters.sh): add merge_chapters.sh

avigad/tutorial,soonhokong/lean-tutorial,fpvandoorn/tutorial,Hodapp87/cs6460_project,fpvandoorn/tutorial,fpvandoorn/tutorial,Hodapp87/cs6460_project,cjmazey/fork_leanprover_tutorial,cjmazey/fork_leanprover_tutorial,avigad/tutorial,soonhokong/lean-tutorial,leanprover/tutorial,leanprover/tutorial,Hodapp87/cs6460_project,cjmazey/fork_leanprover_tutorial,soonhokong/lean-tutorial,avigad/tutorial,leanprover/tutorial