Updated README.

README.md

@@ -1,6 +1,46 @@
 # IP/ASN List
 ## Description
-A Go program that outputs prefixes to a text file per line. Supports ASN lookups (for all prefixes) using [BGPView](https://bgpview.docs.apiary.io/#reference/0/asn-prefixes/view-asn-prefixes) and protecting the web server via authorization token.
+A Go program that acts as a web server. This program loops through all `.json` files in the `lists/` directory and parses each list. Each list can contain an array of prefixes and ASNs. There are lookups performed on the ASNs via [BPFView](https://bgpview.docs.apiary.io/#reference/0/asn-prefixes/view-asn-prefixes)'s API. Afterwards, it outputs all prefixes to a file in the `public/` directory where clients can view them assuming they have the correct authorization header set from the config.
+
+## Why Did I Make This?
+After implementing my own custom filters into [Compressor V1](https://github.com/Dreae/compressor/) to mitigate (D)DoS attacks against GFL's Anycast network, I decided to implement whitelisting functionality for specific services. However, I didn't want to update these files locally on each POP each time I had to add a prefix. Therefore, I decided to create this program and have each POP cURL each list for specific services (with the correct authorization header set) and save them locally every five - ten minutes.
+
+## Config
+You can change settings in the `settings.conf` file which is in JSON format. Here's the default config:
+
+```
+{"token": "CHANGEME", "port": 7030, "updatetime": 15}
+```
+
+* `token` => The authorization header that must be set when accessing the list publicly.
+* `port` => The port the web server binds to.
+* `updatetime` => How often to update all lists.
+
+## Lists
+Each list config needs to have a file with the format `lists/<name>.json`. Here's an example of the test list (`lists/test.json`):
+
+```
+{
+    "ASN": [
+        398129,
+        32590
+    ],
+    "Prefix": [
+        "192.168.90.1/32",
+        "192.168.90.2/32"
+    ]
+}
+```
+
+The above configuration will output all prefixes from ASN's 398129 and 32590 along with the additional prefixes `192.168.90.1/32` and `192.168.90.2/32` to `public/test.txt`.
+
+## Building
+You may use the following commands to build this project.
+
+```
+cd src/
+go build -o ../iplist
+```
 
 ## Credits
 * [Christian Deacon](https://www.linkedin.com/in/christian-deacon-902042186/) - Creator.