Locations Service (#34)

* Locations Proto

* Add Read RPC

* Locations Service

* Add read locks

locations/model/location.go

@@ -0,0 +1,26 @@
+package model
+
+import (
+	"time"
+)
+
+type Location struct {
+	ID        string
+	UserID    string `gorm:"index"`
+	Latitude  float64
+	Longitude float64
+	Timestamp time.Time
+}
+
+// use the user id for the geoindex so only one result is returned per user
+func (l *Location) Id() string {
+	return l.UserID
+}
+
+func (l *Location) Lat() float64 {
+	return l.Latitude
+}
+
+func (l *Location) Lon() float64 {
+	return l.Longitude
+}