fix(launch): Added parameter

doc/architecture/managers/ConfigManager.md

@@ -0,0 +1,133 @@
+# ConfigManager (`assignments::one::ConfigManager`)
+
+## Overview
+
+The `ConfigManager` class is used to be able to store configuration values in a `TOML` file making it
+possible to change project settings without the need of recompiling the codebase.
+
+The [`toml++`](https://marzer.github.io/tomlplusplus/) library is used to parse TOML configuration
+files and provides type-safe access to configuration parameters. It is automatically installed
+using the `FetchContent_Declare` macro inside of the `CMakeLists.txt`.
+
+## Implementation Details
+
+### Dependencies
+- **toml++**: Modern header-only C++17 TOML parser and serializer
+- **rclcpp**: ROS2 C++ client library for logging
+- **filesystem**: C++17 filesystem library for file operations
+- **DatabaseConfig**: Custom data structure for database configuration
+
+### Key Components
+
+#### Constructor
+```cpp
+ConfigManager(rclcpp::Logger logger)
+```
+- Initializes the configuration manager making use of a ROS2 logger
+- Calls `find_config_file()` and `load_config()` for automatic setup
+- Automatically attempts to locate and load configuration from a list of pre-defined paths.
+
+#### Configuration Loading
+
+**`bool load_config(const std::string& config_file_path)`**
+> Returns `true` on successful load, `false` on failure
+
+- Uses `toml::parse_file()`
+- Loads TOML configuration from specified file path
+- Validates file existence before attempting to parse
+- Error handling for:
+  - File not found errors
+  - TOML parsing errors
+  - General I/O exceptions
+- Updates internal `loaded_` state flag
+
+**`std::string find_config_file() const`**
+> Returns first found configuration file path
+> Returns empty string if no configuration file is found
+
+- Automatically searches for configuration files in predefined locations
+- Search paths (in order):
+```cpp
+std::vector<std::string> default_config_paths_ = {
+    "config.toml",
+    "./src/config.toml",
+    "../config.toml",
+    "../../config.toml",
+    "../../../config.toml",
+    "../../../../config.toml",
+    "/etc/ros2_grade_calculator/config.toml"
+};
+```
+#### Configuration Access
+
+**`std::optional<DatabaseConfig> get_database_config() const`**
+> Returns `std::optional<DatabaseConfig>` for safe null handling
+> Returns `std::nullopt` if:
+>   - Configuration is not loaded
+>   - Database section is missing
+>   - Parsing fails due to invalid format
+
+- Calls `parse_database_config()` for actual parsing
+
+**`bool is_loaded() const`**
+> Returns `true` if configuration has been successfully loaded and parsed
+
+- Getter for configuration load status
+- Used by other components to verify configuration availability
+
+### Configuration Parsing
+
+**`DatabaseConfig parse_database_config(const toml::table& config) const`**
+- parser for database configuration section
+- Extracts all database-related parameters with defaults
+
+#### Default Values and Fallbacks
+- **host**: `"localhost"` - Local database server
+- **port**: `5432` - Standard PostgreSQL port
+- **dbname**: `"grades"` - Application-specific database
+- **user**: `"postgres"` - Default PostgreSQL user
+- **password**: `"postgres"` - Default PostgreSQL password
+- **timeout**: `30` seconds - connection timeout
+- **ssl**: `false` - Disabled by default for development
+- **min_connections**: `1` - Minimal connection pool
+- **max_connections**: `10` - connection pool limit
+
+### Logging
+- Uses ROS2 logger with `[CFG]` prefix for configuration operations
+- Includes file paths in log messages
+
+### Usage Examples
+
+#### Automatic Configuration Loading
+```cpp
+// ConfigManager automatically finds and loads configuration
+ConfigManager config_manager(node->get_logger());
+
+if (config_manager.is_loaded()) {
+    auto db_config = config_manager.get_database_config();
+    if (db_config.has_value()) {
+        // Use database configuration
+        DatabaseManager db_manager(db_config.value());
+    }
+}
+```
+
+### Configuration File Format
+
+Example complete TOML configuration:
+
+```toml
+# Database connection settings
+[database]
+host = "localhost"
+port = 5432
+dbname = "grades"
+user = "postgres"
+password = "postgres"
+timeout = 30
+ssl = false
+
+[database.pool]
+min_connections = 1
+max_connections = 10
+```