more updates

pkg/interpolate/interpolate.go

@@ -119,3 +119,20 @@ func Slug(s string) string {
 func HostSlug(hostname string) string {
 	return Slug(strings.ReplaceAll(hostname, ".", "-"))
 }
+
+// PGIdentifier converts a kforge name into a valid unquoted
+// PostgreSQL identifier: lowercase, hyphens and spaces become
+// underscores, all other non-alphanumeric characters are dropped.
+// "prod-my-tenant-myapp" → "prod_my_tenant_myapp"
+func PGIdentifier(s string) string {
+	var b strings.Builder
+	for _, r := range strings.ToLower(s) {
+		switch {
+		case r >= 'a' && r <= 'z', r >= '0' && r <= '9', r == '_':
+			b.WriteRune(r)
+		case r == '-', r == ' ':
+			b.WriteRune('_')
+		}
+	}
+	return strings.Trim(b.String(), "_")
+}