Add TuxiNet branding and document templates

database/migrations/2024_01_01_000009_create_subscriptions_table.php

@@ -0,0 +1,19 @@
+<?php
+
+use PDO;
+
+return function (PDO $pdo): void {
+    $pdo->exec(<<<SQL
+        CREATE TABLE subscriptions (
+            id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
+            user_id INT UNSIGNED NOT NULL,
+            project_id INT UNSIGNED NULL,
+            issue_id INT UNSIGNED NULL,
+            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+            CONSTRAINT fk_subscriptions_user FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE,
+            CONSTRAINT fk_subscriptions_project FOREIGN KEY (project_id) REFERENCES projects(id) ON DELETE CASCADE,
+            CONSTRAINT fk_subscriptions_issue FOREIGN KEY (issue_id) REFERENCES issues(id) ON DELETE CASCADE,
+            INDEX idx_subscriptions_user (user_id)
+        ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+    SQL);
+};