feat(avatar): added server side proxy and cache of gravatar requests

pkg/api/dtos/models.go

@@ -7,6 +7,7 @@ import (
 	"time"
 
 	m "github.com/grafana/grafana/pkg/models"
+	"github.com/grafana/grafana/pkg/setting"
 )
 
 type LoginCommand struct {
@@ -89,5 +90,5 @@ func GetGravatarUrl(text string) string {
 
 	hasher := md5.New()
 	hasher.Write([]byte(strings.ToLower(text)))
-	return fmt.Sprintf("https://secure.gravatar.com/avatar/%x?s=90&default=mm", hasher.Sum(nil))
+	return fmt.Sprintf(setting.AppSubUrl+"/avatar/%x", hasher.Sum(nil))
 }