Updated documentation

Author: HeyJoel

README.md

@@ -9,8 +9,10 @@ This library is a plugin for [Cofoundry](https://www.cofoundry.org/). For more i
 
 ## Overview
 
-Unfinished
+This plugin allows you to send mail using the [SendGrid](https://sendgrid.com/) api. By referencing this package your Cofoundry project will automatically replace the default IMailDispatchService implementation with one that uses SendGrid. Use the following settings to configure the service:
 
+- ***Cofoundry:Plugins:SendGrid:ApiKey*** The api key use when authenticating with the SendGrid api.
+- ***Cofoundry:Plugins:SendGrid:Disabled*** Indicates whether the plugin should be disabled, which means services will not be bootstrapped. Defaults to false.