Add mermaid diagram

Bot/README.md

@@ -1 +1,16 @@
-# WIP Rewrite of Lunaris music bot for discord.
+## How commands from Discord gets executed
+```mermaid
+flowchart TD
+    Program[Program] -->|Register| EventListener
+    EventListener[DiscordEventListener] --> A
+    A[MessageReceivedHandler] --> B(Message)
+    B --> C{Send to correct command by 
+            looking at commandName}
+
+    C -->|JoinCommand| D[JoinHandler]
+    C -->|PlayCommand| E[PlayHandler]
+    C -->|HelloCommand| F[HelloHandler]
+    C -->|GoodbyeCommand| G[GoodbyeHandler]
+```
+
+Program registers an event listener ```DiscordEventListener``` which publish a message ```C# await Mediator.Publish(new MessageReceivedNotification(arg), _cancellationToken);```