Add Symfony version informations

.gitignore

+.idea/

README.md

 
 It's benchmark bundles for almost all Symfony versions.
 
+Symfony 2.0 to 2.3 : use [2.0 version](https://github.com/phpbenchmarks/symfony/tree/2.0).
+
+Symfony 2.4 to latest : use [1.0 version](https://github.com/phpbenchmarks/symfony).
+
 You can find how we benchmark it [here](http://www.phpbenchmarks.com/en/benchmark-protocol).
 
 ## Symfony
 
-You can find all Symfony benchmarks [here](http://www.phpbenchmarks.com/fr/benchmark/apache-bench/php-7.1/select-version/symfony.html)
+You can find all Symfony benchmarks [here](http://www.phpbenchmarks.com/fr/benchmark/apache-bench/php-7.1/select-version/symfony.html).