fix (core init): Handle preload with no members.

Fixes an issue where bot would crash when loaded with no active members.

bot/core/module.py

@@ -46,6 +46,7 @@ async def preload_guild_configuration(client):
     Loads the plain guild configuration for all guilds the client is part of into data.
     """
     guildids = [guild.id for guild in client.guilds]
+    if guildids:
         rows = client.data.guild_config.fetch_rows_where(guildid=guildids)
         client.log(
             "Preloaded guild configuration for {} guilds.".format(len(rows)),
@@ -59,6 +60,7 @@ async def preload_studying_members(client):
     Loads the member data for all members who are currently in voice channels.
     """
     userids = list(set(member.id for guild in client.guilds for ch in guild.voice_channels for member in ch.members))
+    if userids:
         rows = client.data.lions.fetch_rows_where(userid=userids)
         client.log(
             "Preloaded member data for {} members.".format(len(rows)),