adding missing readme files (#123)

Author: pdelewski

README.md

@@ -0,0 +1,48 @@
+# OpenTelemetry Symfony auto-instrumentation
+
+## Requirements
+
+* OpenTelemetry extension
+* OpenTelemetry SDK and exporters (required to actually export traces)
+
+## Overview
+Currently only root span creation is supported (Symfony\Component\HttpKernel\HttpKernel::handle hook).
+
+To export spans, you will need to create and register a `TracerProvider` early in your application's
+lifecycle. This can be done either manually or using SDK autoloading.
+
+### Using SDK autoloading
+
+See https://github.com/open-telemetry/opentelemetry-php#sdk-autoloading
+
+### Manual setup
+
+```php
+<?php
+require_once 'vendor/autoload.php';
+
+$tracerProvider = /*create tracer provider*/;
+$scope = \OpenTelemetry\API\Common\Instrumentation\Configurator::create()
+    ->withTracerProvider($tracerProvider)
+    ->activate();
+
+//your application runs here
+
+$scope->detach();
+$tracerProvider->shutdown();
+```
+
+## Installation via composer
+
+```bash
+$ composer require open-telemetry/opentelemetry-auto-symfony
+```
+
+## Installing dependencies and executing tests
+
+From Symfony subdirectory:
+
+```bash
+$ composer install
+$ ./vendor/bin/phpunit tests
+```