Router not loading on Travis CI

| Q | A
| ----------------- | ---
| Bug? |yes
| New Feature? | no
| Framework | Laravel
| Framework version | 5.4
| Package version | 1.0.0-beta8
| PHP version |5.6.32

#### Actual Behaviour
Ps: I'm using `Laravel 5.4` and `"dingo/api": "1.0.0-beta8",`
On Travis the router is not registered in the service container.

Describe the behaviour you're experiencing. Do not just copy and paste a random error message and expect help.

```
PHP Fatal error: Uncaught exception 'Illuminate\Contracts\Container\BindingResolutionException' with message 'Target [Dingo\Api\Contract\Routing\Adapter] is not instantiable while building [Dingo\Api\Routing\Router].' in /home/travis/build/andela-tolotin/inventory-manager/vendor/laravel/framework/src/Illuminate/Container/Container.php:895
Stack trace:
#0 /home/travis/build/andela-tolotin/inventory-manager/vendor/laravel/framework/src/Illuminate/Container/Container.php(735): Illuminate\Container\Container->notInstantiable('Dingo\\Api\\Contr...')
#1 /home/travis/build/andela-tolotin/inventory-manager/vendor/laravel/framework/src/Illuminate/Container/Container.php(608): Illuminate\Container\Container->build('Dingo\\Api\\Contr...')
#2 /home/travis/build/andela-tolotin/inventory-manager/vendor/laravel/framework/src/Illuminate/Container/Container.php(575): Illuminate\Container\Container->resolve('Dingo\\Api\\Contr...')
#3 /home/travis/build/andela-tolotin/inventory-manager/vendor/laravel/framework/src/Illuminate/Container/Container in /home/travis/build/andela-tolotin/inventory-manager/vendor/laravel/framework/src/Illuminate/Container/Container.php on line 895
Fatal error: Uncaught exception 'Illuminate\Contracts\Container\BindingResolutionException' with message 'Target [Dingo\Api\Contract\Routing\Adapter] is not instantiable while building [Dingo\Api\Routing\Router].' in /home/travis/build/andela-tolotin/inventory-manager/vendor/laravel/framework/src/Illuminate/Container/Container.php on line 895
Illuminate\Contracts\Container\BindingResolutionException: Target [Dingo\Api\Contract\Routing\Adapter] is not instantiable while building [Dingo\Api\Routing\Router]. in /home/travis/build/andela-tolotin/inventory-manager/vendor/laravel/framework/src/Illuminate/Container/Container.php on line 895

```

#### Expected Behaviour

Describe the behaviour you're expecting.
The router should work in the test environment like the way it's working on the local and prod environments.
#### Steps to Reproduce

List all the steps needed to reproduce the issue you're having. Make sure to include code (affected models, configurations),
any screenshots and/or other resources that may help us understand what's going on.

#### Possible Solutions

If you have any ideas on how to solve the issue, add them here, otherwise you can omit this part.