trying to get it running without docker

When I try to get it running without docker, I get the following error: `Environment variable not found: "DATABASE_URL".`

My `.env` file looks like this:
```
KERNEL_CLASS=App\Kernel
APP_SECRET=s$cretf0rt3st
SYMFONY_DEPRECATIONS_HELPER=999999

DATABASE_URL='mysql://root:@localhost:3306/test'
```

I'm new to symfony and I can't figure out the problem.