Ensure entry exists before trying to set anything

cogs/config.py

@@ -726,6 +726,9 @@ WHERE
         except AttributeError:
             await ctx.send(f"{option} is not a valid config option. Use {ctx.prefix}config to list all config options")
         else:
+            # First make sure there's an entry for this guild before doing anything
+            await ctx.bot.db.execute("INSERT INTO guilds(id) VALUES ($1)", ctx.guild.id)
+
             try:
                 await coro(ctx, setting=setting)
             except WrongSettingType as exc: