update readme request for email announcement

[memoht]

I am using a paul_revere announcement successfully on my site, but having trouble getting it to work with email. An example of usage for email would be greatly appreciated.

Here is what I tried to add to the body of an existing email message. The model in this case is ad_request:

Announcement(s): <%= render :partial => "announcements/email_announcement" %>

The result is:
A ActionView::Template::Error occurred in ad_requests#create:
undefined local variable or method `current_announcement' for #<#Class:0x0000010876e158:0x00000108764d10>