Linode support (#144)

docs/linode.md

@@ -0,0 +1,34 @@
+# Linode
+
+## Configuration
+
+### Example
+
+```json
+{
+  "settings": [
+    {
+      "provider": "linode",
+      "domain": "domain.com",
+      "host": "@",
+      "token": "token",
+      "ip_version": "ipv4"
+    }
+  ]
+}
+```
+
+### Compulsory parameters
+
+- `"domain"`
+- `"host"` is your host and can be a subdomain or `"@"` or `"*"`
+- `"token"`
+
+### Optional parameters
+
+- `"ip_version"` can be `ipv4` (A records) or `ipv6` (AAAA records), defaults to `ipv4 or ipv6`
+
+## Domain setup
+
+1. Create a personal access token with `domains` set, with read and write privileges, ideally that never expires. You can refer to [@AnujRNair's comment](https://github.com/qdm12/ddns-updater/pull/144#discussion_r559292678) and to [Linode's guide](https://www.linode.com/docs/products/tools/cloud-manager/guides/cloud-api-keys).
+1. The program will create the A or AAAA record for you if it doesn't exist already.