implement purge command

nomen/settings.py

@@ -25,7 +25,28 @@ class Settings(Cog):
         """
         Deletes all user data stored in Nomen
         """
-        pass
+
+        msg = f"""\
+Are you sure you wish to delete **ALL** data across **ALL** servers? (y/N)
+NOTE: If you have currently opted-out, this will opt you back in.
+
+You may want to `{ctx.clean_prefix}nomen export` first"""
+
+        to_purge = await confirm(ctx, msg)
+
+        if to_purge:
+            await self.bot.db.execute(
+                """
+            DELETE FROM keywords WHERE user_id=?;
+            DELETE FROM users WHERE user_id=?;
+            DELETE FROM user_ignores WHERE user_id=?;
+            """,
+                (ctx.author.id,),
+            )
+            await self.bot.db.commit()
+            await ctx.send("Deleted all user data.")
+        else:
+            await ctx.send("Cancelled.")
 
     @nomen.command(name="import")
     @guild_only()