Remove email_validator gem and allow apostrophe as a valid character in email.

Gemfile

@@ -50,9 +50,6 @@ gem "grape", "~> 0.6.1"
 gem "grape-entity", "~> 0.4.2"
 gem 'rack-cors', require: 'rack/cors'
 
-# Email validation
-gem "email_validator", "~> 1.4.0", :require => 'email_validator/strict'
-
 # Format dates and times
 # based on human-friendly examples
 gem "stamp"

Gemfile.lock

@@ -110,8 +110,6 @@ GEM
     email_spec (1.5.0)
       launchy (~> 2.1)
       mail (~> 2.2)
-    email_validator (1.4.0)
-      activemodel
     emoji (1.0.1)
       json
     enumerize (0.7.0)
@@ -591,7 +589,6 @@ DEPENDENCIES
   diffy (~> 3.0.3)
   dropzonejs-rails
   email_spec
-  email_validator (~> 1.4.0)
   enumerize
   factory_girl_rails
   ffaker

lib/gitlab/email_validator.rb

+# Based on https://github.com/balexand/email_validator
+# 
+# Extended to use only strict mode with following allowed characters:
+# ' - apostrophe
+#
+# See http://www.remote.org/jochen/mail/info/chars.html
+#
+class EmailValidator < ActiveModel::EachValidator
+  @@default_options = {}
+
+  def self.default_options
+    @@default_options
+  end
+
+  def validate_each(record, attribute, value)
+    options = @@default_options.merge(self.options)
+    unless value =~ /\A\s*([-a-z0-9+._']{1,64})@((?:[-a-z0-9]+\.)+[a-z]{2,})\s*\z/i
+      record.errors.add(attribute, options[:message] || :invalid)
+    end
+  end
+end