Setting up GIT for Symfony2 project: why add web/bundles folder to gitignore
The reason to put the web/bundles folder to ignore is that it's generated by running the app/console assets:install web command which is also run automatically at the end of the bin/vendors install run. Whatever you have in YourBundle/Resources/public goes to web/bundles/your.
If you don't want to install assets each time you change them while developing, use the --symlink argument:
app/console assets:install --symlink web