Major refactorings.

Introduce summaries.

models/summary.go

@@ -0,0 +1,28 @@
+package models
+
+import (
+	"time"
+)
+
+const (
+	NSummaryTypes   uint8 = 4
+	SummaryProject  uint8 = 0
+	SummaryLanguage uint8 = 1
+	SummaryEditor   uint8 = 2
+	SummaryOS       uint8 = 3
+)
+
+type Summary struct {
+	UserID           string        `json:"user_id"`
+	FromTime         *time.Time    `json:"from"`
+	ToTime           *time.Time    `json:"to"`
+	Projects         []SummaryItem `json:"projects"`
+	Languages        []SummaryItem `json:"languages"`
+	Editors          []SummaryItem `json:"editors"`
+	OperatingSystems []SummaryItem `json:"operating_systems"`
+}
+
+type SummaryItem struct {
+	Key   string        `json:"key"`
+	Total time.Duration `json:"total"`
+}