Update file names for documentation

README.md

@@ -18,7 +18,7 @@ Tools
 * Docker - engine 18.06.0+ or later, compose 1.29.2 or later, compose file version 3.7 to be supported
 * Git
 
-More on configuration and setting of environment variables is available in [Configuration](docs/configuration.md).
+More on configuration and setting of environment variables is available in [Configuration](docs/CONFIGURATION.md).
 
 ### Start application
 
@@ -31,7 +31,7 @@ Start application and database via Docker. For first time users, recommended way
 *  browse to
     * `http://localhost:8080/swagger-ui.html`
 
-More on how to start application is available in [Start application](docs/start_application.md).
+More on how to start application is available in [Start application](docs/START_APPLICATION.md).
 
 ### Integration tests with Docker containers