Feat(Routes file & Student CRUD's first mehods)

[j-obiols]

This pull request:

1 - According an approach by @elpupas, creates a routes file named v1.php instead of api.php (v1 stands for version 1) and modifies accordingly the file RouteServiceProvider.php, to indicate this file's location and to set API calls prefixes (api/v1).

2 - Studying and developing an approach by @androsrivas, this pull request sets an abstract class named UserRequest that extends FormRequest and defines User's register validation rules.

In this abstract class, we have overwritten the method failedValidation(...) from original FormRequest class, in order to send validation errors messages to API calls when needed.

To Store Admins, Students or Recruiters, other Form Requests will be created extending User Request and setting new validation register rules for each case.

A first version of StoreStudentRequest is already included in this commit. Notice that, in order to send all validation rules to the Controller when required, we've had to modify the function rules(). Now it will return an array merging the Parent::rules with this class own validation rules.

With this approach:

a) Store methods in each model's controller are simpler.
b) Each StoreModelRequest is also simpler, as it doesn't have to rewrite User validation rules, it just has to call for them.

3 - In Store methods, we create a $user and then, we a create a $user -> student (the relation being previously defined in the Models...). This way the foreign Key is set automatically. This system can be applied to admins and recruiters.

As two entities must be created, a DB::transaction is implemented to avoid database inconsistency, following a proposal by @CloudSalander.

[CloudSalander]

It's really nice to see how you increase your technical level with the approach that you're using on that feature.
Great.!
Can you fix the two littles conflicts that we have?

Thanks :)

[j-obiols]

Hello, I have tried to solve the conflicts by accepting develop branch settings about Laravel Pint, but I believe there is something there to be fixed...In my branch I had the latest version (5) because I ran composer update after one pull, and in composer is set v.4...

[CloudSalander]

Okey, we will check Pint issues. Now, for the sake of the work of your partners I will merge the branch.
Thank you!