Add fallbackEmail to user data model

src/user.js

@@ -166,6 +166,7 @@ function createUser(username, password, email, displayName, auditSource, options
                 id: 'uid-' + uuid.v4(),
                 username: username,
                 email: email,
+                fallbackEmail: email,   // for new users the fallbackEmail is also the default email
                 password: new Buffer(derivedKey, 'binary').toString('hex'),
                 salt: salt.toString('hex'),
                 createdAt: now,
@@ -399,6 +400,12 @@ function updateUser(userId, data, auditSource, callback) {
         if (error) return callback(error);
     }
 
+    if (data.fallbackEmail) {
+        data.fallbackEmail = data.fallbackEmail.toLowerCase();
+        error = validateEmail(data.fallbackEmail);
+        if (error) return callback(error);
+    }
+
     userdb.get(userId, function (error) {
         if (error && error.reason === DatabaseError.NOT_FOUND) return callback(new UserError(UserError.NOT_FOUND));
         if (error) return callback(new UserError(UserError.INTERNAL_ERROR, error));