register the module 'colors' to devDependencies

package.json

@@ -58,7 +58,6 @@
     "botkit": "~0.1.1",
     "check-node-version": "^2.0.1",
     "cli": "~1.0.1",
-    "colors": "^1.1.2",
     "connect-flash": "~0.1.1",
     "connect-redis": "^3.3.0",
     "cookie-parser": "^1.4.3",
@@ -123,6 +122,7 @@
   },
   "devDependencies": {
     "chai": "^4.0.2",
+    "colors": "^1.1.2",
     "commander": "^2.11.0",
     "easy-livereload": "^1.2.0",
     "mocha": "^3.2.0",