Add Plan page with day planner

backend/service/dataStore.go

@@ -0,0 +1,19 @@
+package service
+
+import (
+	"time"
+)
+
+type DataStore interface {
+	WriteJournalEntry(interface{}) error
+	GetJournalEntryForDate(time.Time) (interface{}, error)
+
+	WritePlanDay(interface{}) error
+	GetPlanDayForDate(time.Time) (interface{}, error)
+
+	WritePlanWeek(interface{}) error
+	GetPlanWeekForDate(time.Time) (interface{}, error)
+
+	WritePlanMonth(interface{}) error
+	GetPlanMonthForDate(time.Time) (interface{}, error)
+}