Add husky to prevent commit without green tests

package.json

@@ -18,6 +18,8 @@
   },
   "repository": "lesspass/cli",
   "scripts": {
+    "precommit": "npm test",
+    "prepush": "npm test",
     "test": "ava"
   },
   "dependencies": {
@@ -29,6 +31,7 @@
   },
   "devDependencies": {
     "ava": "^0.18.2",
-    "execa": "^0.6.0"
+    "execa": "^0.6.0",
+    "husky": "^0.13.2"
   }
 }