Adding Phone To helper like mail_to for handling phone numbers

Adding Phone To helper like mail_to for handling phone numbers

Useful for mobile browsers and desktop browser with phone supported software.

Creates a tel link tag to the specified +phone_number+

Accepts blocks

Could this be simplified to just:

```ruby
def phone_to(phone_number, *args, &block)
  link_to(phone_number, *args, &block)
end
```