Add "behind proxy" mode to use forwarded IP headers

.env.example

@@ -2,5 +2,6 @@ DEBUG=false
 DEV_MODE=false
 APP_LISTEN_ADDRESS=127.0.0.1
 APP_LISTEN_PORT=3000
+APP_BEHIND_PROXY=false
 DATABASE_LOCATION=./people.db
 SESSIONS_LOCATION=./sessions.db

helpers/config.go

@@ -12,6 +12,7 @@ type Config struct {
 	App     struct {
 		ListenAddress string `env:"APP_LISTEN_ADDRESS"`
 		ListenPort    uint   `env:"APP_LISTEN_PORT"`
+		BehindProxy   bool   `env:"APP_BEHIND_PROXY"`
 	}
 	Database struct {
 		Location string `env:"DATABASE_LOCATION"`

main.go

@@ -67,10 +67,17 @@ func main() {
 
 	pongo2.RegisterFilter("time_diff", helpers.TemplTimeDiff)
 
-	app := fiber.New(fiber.Config{
+	fiberConfig := fiber.Config{
 		Views:        engine,
 		ErrorHandler: helpers.FiberErrorHandler,
-	})
+	}
+
+	// If app behind proxy, use headers for IP
+	if config.App.BehindProxy {
+		fiberConfig.ProxyHeader = fiber.HeaderXForwardedFor
+	}
+
+	app := fiber.New(fiberConfig)
 
 	if config.DevMode {
 		app.Static("/static", "./static")