Add favicon (#288)

handler/routes.go

@@ -6,6 +6,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"net/http"
+	"os"
 	"sort"
 	"strings"
 	"time"
@@ -32,6 +33,15 @@ func Health() echo.HandlerFunc {
 	}
 }
 
+func Favicon() echo.HandlerFunc {
+	return func(c echo.Context) error {
+		if favicon, ok := os.LookupEnv(util.FaviconFilePathEnvVar); ok {
+			return c.File(favicon)
+		}
+		return c.Redirect(http.StatusFound, util.BasePath+"/static/custom/img/favicon.ico")
+	}
+}
+
 // LoginPage handler
 func LoginPage() echo.HandlerFunc {
 	return func(c echo.Context) error {