add admin api key for creating accounts

lib/tokens/admin.go

@@ -0,0 +1,17 @@
+package tokens
+
+import (
+	"github.com/labstack/echo/v4"
+	"github.com/labstack/echo/v4/middleware"
+)
+
+func AdminTokenMiddleware(token string) echo.MiddlewareFunc {
+	if token == "" {
+		return func(next echo.HandlerFunc) echo.HandlerFunc {
+			return next
+		}
+	}
+	return middleware.KeyAuth(func(auth string, c echo.Context) (bool, error) {
+		return auth == token, nil
+	})
+}