move cssnano into dependencies

package.json

@@ -9,6 +9,7 @@
     "aws-sdk": "^2.67.0",
     "bcrypt": "^1.0.2",
     "bluebird": "^3.5.0",
+    "cssnano": "^3.10.0",
     "ff": "0.2.1",
     "glob": "7.1.1 ",
     "gulp": "3.9.1",
@@ -32,7 +33,6 @@
   },
   "devDependencies": {
     "@types/node": "7.0.29",
-    "cssnano": "^3.10.0",
     "gulp-nodemon": "2.2.1",
     "gulp-postcss": "^7.0.0",
     "gulp-typescript": "^3.1.6",