Update button on Edit Screen

[henriquefacioli]

The "enviar" (send) button should be replaced with an "atualizar" (update) button if the data is already on server and is possible to edit it. To do so, for now, it is need to do a mutation that will do like:

mutation updateTimeentries {
  delTimeEntry(date: '2018-01-25')
  addTimeEntry(TimeEntry)
}

but, to avoid inserting before deleting on async calls, maybe should create a new mutation editTimeEntry(TimeEntry) that would do that in one call. This should be implemented on server/schema/resolver.js

[msandrini]

This was done recently.