Add admin user, and an option to add a user admin on startup

internal/jwtauth/jwt.go

@@ -1,10 +1,12 @@
 package jwtauth
 
 import (
+	"strconv"
+
 	"github.com/golang-jwt/jwt/v5"
 )
 
-func GenerateJwtToken(username string) (string, error) {
+func GenerateJwtToken(username string, admin bool) (string, error) {
 	var s string
 	key, err := GetJwtKey()
 	if err != nil {
@@ -12,8 +14,9 @@ func GenerateJwtToken(username string) (string, error) {
 	}
 	t := jwt.NewWithClaims(jwt.SigningMethodHS256,
 		jwt.MapClaims{
-			"iss": "bibliomane",
-			"sub": username,
+			"iss":   "bibliomane",
+			"sub":   username,
+			"admin": strconv.FormatBool(admin),
 		})
 	return t.SignedString(key)
 }