use local timezone

Because we are reading a time at -03 timezone we should not consider it at +00. Otherwise clients get -06 time when converting +00 to -03.

```ruby
require 'json'
require 'open-uri'
data = JSON.parse(open("http://api.viradacultural.vertigem.xxx/stages/2/attractions/814").read)
puts Time.parse data['starts_at']
```