Updated readme.md.

readme.md

@@ -1,3 +1,58 @@
 # GoDaddy DDNS
 
 Rust application to update GoDaddy DNS Records via REST API.
+
+It order for the application to work, there needs to be a file called `records.json` placed in `$HOME/.godaddy-ddns` 
+with the following structure:
+
+```json
+{
+  "records": 
+  [
+    {
+      "name": string,
+      "record_type": string,
+      "data": string, // Optional
+      "port": number, // Optional - SRV Only. 
+      "priority": number, // Optional - MX and SRV Only. 
+      "protocol": string, // Optional - SRV Only.
+      "service": string, // Optional - SRV Only. 
+      "ttl": number,
+      "interpolate": boolean, // Optional
+      "weight": number // Optional - SRV Only.
+    }
+  ]
+}
+```
+
+### Fields of interest 
+
+* name: `{string}` - Name of the record.
+* record_type: `{string}` - Type of the record (A, AAAA, CAA, CNAME, MX, NS, SRV, TXT). 
+* data: `{string}` (optional) - Value of the record. (Useful in case of a hard-coded record or interpolation)
+* interpolate: `{boolean}` (optional) - When set to true, the application will write the current ip in the {ip} tag of the data field.
+
+Example of use (with a given IP of 8.8.8.8) :
+
+```json
+{
+  "records": [
+    {
+      "name": "@",
+      "record_type": "A",
+      "ttl": 600
+    },
+    {
+      "name": "@",
+      "record_type": "TXT",
+      "ttl": 3600,
+      "data": "\"v=spf1 ip4:{ip} -all\"", // Result: "v=spf1 ip4:8.8.8.8 -all"
+      "interpolate": true
+    }
+  ]
+}
+```
+
+
+
+