Update README.md

Updated the README to be less awful and reflect the updated support for handling program shutdown.

README.md

@@ -1,6 +1,10 @@
+[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
 # go-cddns
 Golang client for dynamically updating cloudflare DNS records on a specified interval. Useful if you're using Cloudflare to point to a device with a dynamic IP Address
 
+## Installation
+go get -u github.com/nickrobison/go-cddns
+
 ## Usage
 
 Create a config.json with the following structure:
@@ -11,6 +15,13 @@ Create a config.json with the following structure:
   "Key": "{Cloudflare API Key}",
   "Email": "{Cloudflare Email Address}",
   "DomainName": "{Cloudflare domain to modify}",
-  "RecordName": "{Array of DNS records to update}"
+  "RecordName": "{Array of DNS records to update}",
+  "Remove": "{Boolean of whether or not to remove the records on shutdown}"
   }
   ```
+## Notes
+
+* The update interval must be more than 5 minutes, per the WhatIsMyIP API [rules](http://whatismyipaddress.com/api).
+* The records names must be FQDNs, even though they don't appear in the cloudflare dashboard as such.
+* If the Remove field is set to true, the listed DNS records will be removed when the program exits.
+