Added reference for config

Daemon-Config-Reference.md

@@ -0,0 +1,14 @@
+# Daemon configuration
+
+The daemon is configurable by config.txt.
+This file must be in the same directory as the binary.
+
+### Configuration Values
+`port` : The port where the server listens. Must be a valid port.
+`interface` : The sniffer interface you want to use.
+
+### Example for config.txt
+```
+port=1234
+interface=lo
+```