disable the Vue production warning in development and testing

app/assets/javascripts/commons/vue.js

@@ -0,0 +1,8 @@
+import Vue from 'vue';
+import VueResource from 'vue-resource';
+
+Vue.use(VueResource);
+
+if (process.env.NODE_ENV !== 'production') {
+  Vue.config.productionTip = false;
+}

config/webpack.config.js

@@ -18,7 +18,7 @@ var config = {
   context: path.join(ROOT_PATH, 'app/assets/javascripts'),
   entry: {
     common:               './commons/index.js',
-    common_vue:           ['vue', 'vue-resource'],
+    common_vue:           './commons/vue.js',
     common_d3:            ['d3'],
     main:                 './main.js',
     blob_edit:            './blob_edit/blob_edit_bundle.js',