feat: add method for querying the current AUTO_INCREMENT for a table (#5)

This will be used to retrieve the primary key for newly inserted rows.

Reviewed-on: https://codeberg.org/vlw/wp/pulls/5

src/Database.php

@@ -76,6 +76,19 @@
 			parent::__construct();
 		}
 
+		/**
+		 * Return the current AUTO_INCREMENT value for a given table
+		 *
+		 * @param string $table
+		 * @return int
+		 */
+		public function latest(string $table): int {
+			return $this->execute_query("SELECT AUTO_INCREMENT FROM information_schema.TABLES WHERE TABLE_SCHEMA = ? AND TABLE_NAME = ?", [
+				self::$name,
+				self::get_table($table)
+			])->fetch_assoc()["AUTO_INCREMENT"];
+		}
+
 		/**
 		 * Fetch and set the WordPress siteurl from the options table
 		 *