added env desc to readme

Signed-off-by: Prati28 <[email protected]>

README.md

@@ -18,6 +18,7 @@ File handler utilizing TUS and MinIO with DRS-Filer integration.
 - [Basic Usage](#basic-usage)
 - [Installation](#installation)
 - [Development](#development)
+- [Environment Variables](#environment-variables)
 - [Contributing](#contributing)
 - [Code of Conduct](#code-of-conduct)
 - [Versioning](#versioning)
@@ -157,6 +158,14 @@ make u
 > **Note**: This is not the complete list of commands, run `make` to find out if
 > more have been added.
 
+## Environment Variables
+
+### `TUS_FOCA_CONFIG_PATH`
+
+- **Description:** Specifies the path to the configuration file for the FOCA app.
+- **Usage:** The FOCA app uses this environment variable to locate the configuration file. If not set, the app will use a default configuration path.
+- **Error Handling:** If the configuration file is not found at the specified path or the default path, a `FileNotFoundError` will be raised.
+
 ## Contributing
 
 This project is a community effort and lives off _your_ contributions, be it in
@@ -213,4 +222,4 @@ To get in touch with us, please use one of the following routes:
 [license]: LICENSE
 [logo-elixir]: images/logo-elixir.svg
 [logo-elixir-cloud-aai]: images/logo-elixir-cloud-aai.svg
-[semver]: https://semver.org/
+[semver]: https://semver.org/