feat: v2 (#599)

Read https://github.com/filebrowser/filebrowser/pull/575.

auth/auth.go

@@ -0,0 +1,15 @@
+package auth
+
+import (
+	"net/http"
+
+	"github.com/filebrowser/filebrowser/v2/users"
+)
+
+// Auther is the authentication interface.
+type Auther interface {
+	// Auth is called to authenticate a request.
+	Auth(*http.Request) (*users.User, error)
+	// SetStorage attaches the Storage instance.
+	SetStorage(*users.Storage)
+}