Add attribute template

Template.php

@@ -0,0 +1,68 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Fig\Attributes;
+
+/**
+ * One-Line summary of what the attribute does (PLAIN TEXT!)
+ *
+ * ## Target audience
+ *
+ * Implementors
+ * : Who should handle this attribute? Example: "static analysis tools"
+ * Users
+ * : Who adds this attribute to their code? Example: "packages that want to
+ *   safeguard their functions via static analysis"
+ *
+ * ## Purpose
+ *
+ * Long explanation of what the attribute does and why it is relevant.
+ *
+ * Use citations[^citation] or [Links](https://example.com) in your text to make
+ * sure people understand the relevance and where you got your ideas from.
+ *
+ * ## When should the attribute be applied ?
+ *
+ * If your Attribute has preconditions for usage you MUST use the keywords
+ * described in [RFC 2119](https://datatracker.ietf.org/doc/html/rfc2119).
+ * You SHOULD list them prominently.
+ *
+ * **Note:** DocBlock content MUST be Markdown formatted. Check out the
+ *   [Markdown-Guide](https://www.markdownguide.org/) for possible formatting
+ *   and keep in mind that the short description should not contain markdown.
+ *
+ * Keep your lines at a maximum of 80 Characters. It increases readability on
+ * smaller windows.
+ *
+ * Please also use code-snippets where appropriate
+ *
+ * ```php
+ * <?php
+ * echo 'Hello World';
+ * ```
+ *
+ * [^citation] https://en.wikipedia.org/wiki/Citation
+ */
+#[\Attribute(\Attribute::TARGET_CLASS)]
+class Template
+{
+    /**
+     * You MUST describe parameters to your Attribute extensively! You SHOULD use
+     * the well-known Annotations for that.
+     *
+     * Also, you SHOULD describe what the different functions do.
+     *
+     * @param string $name
+     *     The name of this template
+     * @param boolean $expose
+     *     Whether to expose this as an example or not.
+     * @param int[] $luckyNumbers
+     *     The lucky numbers of this week
+     */
+    public function __construct(
+        public readonly string $name,
+        public readonly bool $expose,
+        public readonly array $luckyNumbers
+    ) {}
+}