(guild admin): Add greeting messages.

New `SettingType` `Message` for general message settings.
New setting `greeting_message`.
New setting `greeting_channel`.
New setting `starting_funds`.
New setting `returning_message`.
Add a greeting message hook.
Add initial funds on lion creation.
Data migration v3 -> v4.

bot/core/data.py

@@ -74,6 +74,7 @@ lions = RowTable(
      'workout_count', 'last_workout_start',
      'last_study_badgeid',
      'video_warned',
+     '_timestamp'
      ),
     ('guildid', 'userid'),
     cache=TTLCache(5000, ttl=60*5),

bot/core/lion.py

@@ -2,7 +2,7 @@ import pytz
 
 from meta import client
 from data import tables as tb
-from settings import UserSettings
+from settings import UserSettings, GuildSettings
 
 
 class Lion:
@@ -41,7 +41,13 @@ class Lion:
         if key in cls._lions:
             return cls._lions[key]
         else:
-            tb.lions.fetch_or_create(key)
+            lion = tb.lions.fetch(key)
+            if not lion:
+                tb.lions.create_row(
+                    guildid=guildid,
+                    userid=userid,
+                    coins=GuildSettings(guildid).starting_funds.value
+                )
             return cls(guildid, userid)
 
     @property