BE-Athlete seed times

[MarisiaS]

This PR addresses issue #56

Implementation

1. backend/api/CustomField.py Created custom field subclass HeatDurationField of DurationField.

Added the following option:

• NT corresponds to 200 days. It will be use when an athlete does not have a seed time for an event.
• NS corresponds to 300 days. It will be use when an athlete does not show up for a heat.
• DQ corresponds to 400 days. It will be use when an athlete gets disqualified for a heat.

2. backend/api/serializers/AthleteSeedTimeSerializer.py Created two serializer:

• AthleteSeedTimeSerializer: Used to display athlete ID, athlete full name and athlete seed time.
• UpdateAthleteSeedTimeSerializer: Used to record a time for an specific athlete. The date needed are athlete, date. time. The event_type has to be pass as a context. Validates that the time is positive. And includes a create function to register the record.

3. backend/api/views/AtheleteSeedTimeView.py Created AthleteSeedTimeView. This view contains two methods:

• Get: Given an event_id, uses AthleteSeedTimeSerializer to display the seed time of the athletes in the group corresponding to the given event.
• Post: Uses UpdateAthleteSeedTimeSerializer to add a record on TimeRecord for a specific athlete.

4. backend/api/urls.py Added seed_times/<int:event_id> endpoint