Add capture group example

README.md

@@ -9,6 +9,8 @@ A [maubot](https://github.com/maubot/maubot) that responds to messages that matc
 * [samples/stallman.yaml](samples/stallman.yaml) contains a Stallman interject bot.
 * [samples/random-reaction.yaml](samples/random-reaction.yaml) has an example of
   a randomized reaction to matching messages.
+* [samples/nitter.yaml](samples/nitter.yaml) has an example of matching tweet links
+  and responding with a corresponding nitter.net link.
 
 ## Config format
 ### Templates

samples/nitter.yaml

@@ -0,0 +1,15 @@
+templates:
+    nitter:
+        type: m.room.message
+        content:
+            msgtype: m.text
+            body: https://nitter.net/$${1}/status/$${2}
+
+default_flags:
+- ignorecase
+
+rules:
+    twitter:
+        matches:
+        - https://twitter.com/(.+?)/status/(\d+)
+        template: nitter