Corrected skeleton provider. Add cog for guild listener.

cogs/guild_listener/__init__.py

@@ -0,0 +1,37 @@
+"""
+Defines cog for guild listeners. Contains functions for various guild events.
+"""
+
+from nextcord.ext import commands
+import nextcord
+
+from highscores import highscores_data  # pylint: disable=import-error
+from utilities.data_storage import create_highscore_skeleton  # pylint: disable=import-error
+from utilities.data_storage import save_highscores_data  # pylint: disable=import-error
+
+
+class GuildListener(commands.Cog, name="Guild Listener"):
+    """Sets up message listener."""
+
+    def __init__(self, bot: commands.Bot):
+        self.bot = bot
+
+    @commands.Cog.listener()
+    async def on_guild_join(self, guild: nextcord.Guild):
+        """Listener for Guild Join. Creates skeleton for new guild joined and saves it."""
+        # turning guild id into string because json doesn't support ints as object keys.
+        highscores_data[str(guild.id)] = create_highscore_skeleton()
+        save_highscores_data(highscores_data)
+
+        welcome_message: str = "Hello, I keep track of Highscores for you!"
+        welcome_message += "Currently only supporting RuneScape boss highscores, but will be more dynamic support in future."
+        welcome_message += "For assistance on getting started, use \?register help\."
+
+        guild.system_channel.send(content=welcome_message)
+
+
+# This function will be called when this extension is loaded.
+# It is necessary to add these functions to the bot.
+def setup(bot: commands.Bot):
+    """Adds function to bot"""
+    bot.add_cog(GuildListener(bot))