Add regex for restriction and use.

src/service/util.js

@@ -78,6 +78,19 @@ exports.isEmail = function(data) {
   return re.test(data);
 };
 
+/**
+ * Checks for a valid specific organisation email address.
+ * @param  {string} data   The email address
+ * @return {boolean}       Wether the email address comes from organisation
+ */
+exports.isFromOrganisation = function(data) {
+  if (!this.isString(data)) {
+    return false;
+  }
+  const re = /^([a-z0-9\-.]+)@([a-z0-9.\-]*)esisar\.grenoble-inp\.fr$/;
+  return re.test(data);
+};
+
 /**
  * Normalize email address to lowercase.
  * @param  {string} email   The email address