WIP on user achievements

+ Add MCI codes for points/count
+ Add docs for MCI codes
+ Record in stats, stat log, etc.
* Do not trigger more than once
* Code cleanup & organization, add classes, etc.
* Tweaks to DB table

core/database.js

@@ -196,7 +196,7 @@ const DB_INIT_TABLE = {
                 timestamp           DATETIME NOT NULL,
                 match_field         VARCHAR NOT NULL,
                 match_value         VARCHAR NOT NULL,
-                UNIQUE(user_id, achievement_tag, match_field, match_value),
+                UNIQUE(user_id, achievement_tag, match_field),
                 FOREIGN KEY(user_id) REFERENCES user(id) ON DELETE CASCADE
             );`
         );