added matrix support, added matrix-sdk dependency

docker-compose.yml

@@ -1,15 +1,20 @@
 version: "3"
 services:
   caitsith-discord-bot:
-    image: 
+    image:
     environment:
       VIRTUAL_HOST:
       VIRTUAL_PORT: 80
       LETSENCRYPT_HOST:
-      LETSENCRYPT_EMAIL: 
+      LETSENCRYPT_EMAIL:
       ## Fill these in when you deploy
       # GUILD_ID:
       # DISCORD_TOKEN:
+      #
+      # OR FILL THESE IN INSTEAD
+      # MATRIX_HOMESERVER:
+      # MATRIX_USERNAME:
+      # MATRIX_PASSWORD:
     expose:
       - 80