An authenticated user can update a question

[josepostiga]

Scenario

Given I'm an authenticated user of any type
When I send a PATCH request to /questions/{questionId} with the updatable input and the question was created by me
I expect that question to be updated

Given I'm an authenticated user of any type
When I send a PATCH request to /questions/{questionId} with the updatable input and the question was not created by me
I expect to not be able to update that question

Updatable input

• title: the title of the question. Must be filled.
• slug: the URL friendly identifier, automatically generated based on the title. Must be unique.
• description: the question itself.
• updated_at: timestamp with timezone. Must be automatically updated with the current timestamp of the update action.

Additional requirements

This builds on the features of #25.

[tiagof]

@josepostiga I'll take this one if that's ok...

[tiagof]

PR #41