Dont use ^ and $ on email_regexp

This is a security issue.Also on rails 4 we get the following Error:
```ruby
The provided regular expression is using multiline anchors (^ or $), which may present a security risk. Did you mean to use \A and \z, or forgot to add the :multiline => true option?
```

more info: http://stackoverflow.com/a/577675/534150

review @shingara