Add `/cases` endpoint

[StanleySathler]

Our crawler gathers all confirmed cases from each neighborhood in Belo Horizonte. Our app will show them as a heatmap.

Routes

Only a /GET route is required.

GET /cases

Document scheme

Each document must have the following scheme:

ObjectID refers to the ID auto-generated by MongoDB. Point refers to a special type that stores geolocation data.

{
  id: ObjectID
  neighborhood: String
  location: Point
  serious: Number
  nonSerious: Number
  deaths: Number
}