refactor: introduce concept of durations (resolve #261)

mocks/duration_service.go

@@ -0,0 +1,16 @@
+package mocks
+
+import (
+	"github.com/muety/wakapi/models"
+	"github.com/stretchr/testify/mock"
+	"time"
+)
+
+type DurationServiceMock struct {
+	mock.Mock
+}
+
+func (m *DurationServiceMock) Get(time time.Time, time2 time.Time, user *models.User) ([]*models.Duration, error) {
+	args := m.Called(time, time2, user)
+	return args.Get(0).([]*models.Duration), args.Error(1)
+}