Add history table and modify card_stats

sql/card_stats.sql

@@ -9,5 +9,9 @@ create table card_stats
         references card_set
             on delete cascade,
     score       INTEGER default 1 not null,
-    last_opened INTEGER           not null
+    last_opened INTEGER           not null,
+    added INTEGER not null,
+    fsrs_opened INTEGER,
+    fsrs_memory INTEGER,
+    fsrs_open_time INTEGER
 );