sync: Allow free hint

admin/sync/exercice_defines.go

@@ -12,7 +12,7 @@ import (
 type ExerciceHintParams struct {
 	Filename string
 	Content  string
-	Cost     int64
+	Cost     *int64
 	Title    string
 	NeedFlag []ExerciceDependency `toml:"need_flag,omitempty"`
 }

admin/sync/exercice_hints.go

@@ -36,10 +36,10 @@ func buildExerciceHints(i Importer, exercice fic.Exercice) (hints []importHint,
 		} else {
 			h.Title = fixnbsp(hint.Title)
 		}
-		if hint.Cost <= 0 {
+		if hint.Cost == nil {
 			h.Cost = exercice.Gain / 4
 		} else {
-			h.Cost = hint.Cost
+			h.Cost = *hint.Cost
 		}
 
 		if hint.Filename != "" {