GET /cats/:id

[Cowa]

Add a new route to retrieve a specific cat by its id :
GET /cats/:id

Must returns :

{
  "status": "success"
  "data": {
    "id": "...",
    "link": "http://..."
  }
}

In case of error (?) :

{
  "status": "error",
  "message": "Resource not found"
}

The CatShelter will need some modifications too :

• use a Map instead of an Array for instant access (?)