How to register a bridge in symfony2?

I was trying to setup metabor/statemachine-doctrine-bridge within a symfony2 project. I am used to register new bundles, yet I have no clue how I would get symfony2 to find the bridge.

I tried including it via use statement but it seems to be not enough resulting in the error:

 [Doctrine\Common\Persistence\Mapping\MappingException]                                                                                                              
  The class 'Metabor\Bridge\Doctrine\Statemachine\State' was not found in the chain configured namespaces Hn\AssetDbBundle\Entity, Hn\UserBundle\Entity, FOS\UserBun  
  dle\Entity, FOS\UserBundle\Model

Solution

One needs to both configure the autoloader and point doctrine to the correct entities.

app/config.yml:

orm:
    auto_generate_proxy_classes: "%kernel.debug%"
    auto_mapping: true
    mappings:
        MetaborBridge:
            type: annotation
            dir: %kernel.root_dir%/../vendor/metabor/statemachine-doctrine-bridge/src/Metabor
            prefix: Metabor
            is_bundle: false

composer.json:

...
"autoload": {
    "psr-0": {
        "": "src/",
        "Metabor": "vendor/metabor/statemachine-doctrine-bridge/src/Metabor/",
        "MetaborStd": "vendor/metabor/metabor-std/src/MetaborStd/"
    }
},
...