Add high-level documentation

https://nostr-ruby.com

docs/events/recommend-server.md

@@ -0,0 +1,32 @@
+# Recommend Server
+
+The `Recommend Server` event, has a set of tags with the following structure `['e', <event-id>, <relay-url>, <marker>]`
+
+Where:
+
+- `<event-id>` is the id of the event being referenced.
+- `<relay-url>` is the URL of a recommended relay associated with the reference. Clients SHOULD add a valid `<relay-URL>`
+field, but may instead leave it as `''`.
+- `<marker>` is optional and if present is one of `'reply'`, `'root'`, or `'mention'`.
+Those marked with `'reply'` denote the id of the reply event being responded to. Those marked with `'root'` denote the
+root id of the reply thread being responded to. For top level replies (those replying directly to the root event),
+only the `'root'` marker should be used. Those marked with `'mention'` denote a quoted or reposted event id.
+
+A direct reply to the root of a thread should have a single marked `'e'` tag of type `'root'`.
+
+## Recommending a server
+
+```ruby
+recommend_server_event = user.create_event(
+  kind: Nostr::EventKind::RECOMMEND_SERVER,
+  tags: [
+    [
+      'e',
+      '461544014d87c9eaf3e76e021240007dff2c7afb356319f99c741b45749bf82f',
+      'wss://relay.damus.io'
+    ],
+  ]
+)
+
+client.publish(recommend_server_event)
+```