add license to build

Author: schacon

atlas.json

@@ -2,6 +2,7 @@
   "branch": "master",
   "files": [
     "book/cover.html",
+    "LICENSE.asc",
     "book/preface.asc",
     "book/01-introduction/1-introduction.asc",
     "book/02-git-basics/1-git-basics.asc",
@@ -38,4 +39,4 @@
   },
   "theme": "oreillymedia/pro-git-theme",
   "title": "Pro Git"
-}
+}