Avoid require cache on relaoding assets file on development mode

lib/crowi/index.js

@@ -4,6 +4,7 @@
 var debug = require('debug')('crowi:crowi')
   , pkg = require('../../package.json')
   , path = require('path')
+  , fs = require('fs')
   , sep = path.sep
   , Promise = require('bluebird')
 
@@ -111,9 +112,10 @@ Crowi.prototype.getAssetList = function() {
 
   // reload manifest
   try {
-    this.assets = require(this.publicDir + '/js/manifest.json') || {};
+    this.assets = JSON.parse(fs.readFileSync(this.publicDir + '/js/manifest.json'))|| {};
   } catch (e) {
     // ignore
+    debug('Failed to reload assets on development', e);
   }
   return this.assets;
 };