Repositories are just collections of things. A post repository is a collection of posts, a user repository a collection of users. They allow to abstract away all the persistence details. Yet, many people think of Doctrine repositories as purely related to Doctrine, leading to strange abstractions. Let’s create a normal collection with Symfony and Doctrine today!
Setting up big Symfony components in a blank PHP project helps a lot to understand it. You’ll grasp the main architecture of the component much easier this way. Let’s try to understand Symfony Security by doing exactly this!