feat: subscriptions have personalized notification times (#334)

migrations/000019.php

@@ -0,0 +1,15 @@
+<?php
+/*
+This migration adds a column to the subscriptuons table to store individual choice for how many days before the subscription is up for payment to notify the user
+The default value of 0 means global settings will be used
+*/
+
+/** @noinspection PhpUndefinedVariableInspection */
+$columnQuery = $db->query("SELECT * FROM pragma_table_info('subscriptions') where name='notify_days_before'");
+$columnRequired = $columnQuery->fetchArray(SQLITE3_ASSOC) === false;
+
+if ($columnRequired) {
+    $db->exec('ALTER TABLE subscriptions ADD COLUMN notify_days_before INTEGER DEFAULT 0');
+}
+
+?>