Convert due date string to millisecond format.

db/migrations/mysql/000101_create_true_up_review_history.up.sql

@@ -1,5 +1,5 @@
 CREATE TABLE IF NOT EXISTS TrueUpReviewHistory (
-	DueDate VARCHAR(10),
+	DueDate bigint(20),
 	Completed boolean,
     PRIMARY KEY (duedate)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

db/migrations/postgres/000101_create_true_up_review_history.up.sql

@@ -1,5 +1,5 @@
 CREATE TABLE IF NOT EXISTS trueupreviewhistory (
-	duedate VARCHAR(10),
+	duedate bigint,
 	completed boolean,
     PRIMARY KEY (duedate)
 );