Added README and updated go.mod for compatibility with older versions

README.org

@@ -0,0 +1,25 @@
+* Kazoo Firewall Agent
+Used in conjunction with ~call_shield~ Kazoo application.
+
+** Installation
+*** Build
+- You must have go v1.20 or later installed.
+- clone the repo in the usual way
+#+BEGIN_SRC sh
+cd kazoo_firewall_agent
+go build
+#+END_SRC
+*** Install
+#+BEGIN_SRC sh
+mkdir -p /opt/kazoo_firewall_agent
+cp ./kazoo_firewall_agent /opt/kazoo_firewall_agent
+cp ./kazoo_firewall_agent.service /etc/systemd/system/
+cp ./kazoo_firewall_agent_config.json.sample /opt/kazoo_firewall_agent/
+systemctl daemon-reload
+#+END_SRC
+*** Enable the Service
+-> Make sure you have FirewallD installed and running.
+#+BEGIN_SRC sh
+systemctl enable kazoo_firewall_agent
+systemctl start kazoo_firewall_agent
+#+END_SRC

go.mod

@@ -1,6 +1,6 @@
 module kazoo_firewall_agent
 
-go 1.22.2
+go 1.20
 
 require (
 	github.com/google/uuid v1.6.0 // indirect