New form to change grade

works.go

@@ -251,6 +251,26 @@ func declareAPIAdminWorksRoutes(router *gin.RouterGroup) {
 
 	gradesRoutes := worksRoutes.Group("/grades/:gid")
 	gradesRoutes.Use(gradeHandler)
+	gradesRoutes.PUT("", func(c *gin.Context) {
+		current := c.MustGet("grade").(*WorkGrade)
+
+		var new WorkGrade
+		if err := c.ShouldBindJSON(&new); err != nil {
+			c.AbortWithStatusJSON(http.StatusBadRequest, gin.H{"errmsg": err.Error()})
+			return
+		}
+
+		new.Id = current.Id
+
+		grade, err := new.Update()
+		if err != nil {
+			log.Println("Unable to Update grade:", err)
+			c.AbortWithStatusJSON(http.StatusInternalServerError, gin.H{"errmsg": "An error occurs during grade update."})
+			return
+		}
+
+		c.JSON(http.StatusOK, grade)
+	})
 	gradesRoutes.DELETE("", func(c *gin.Context) {
 		g := c.MustGet("grade").(*WorkGrade)
 
@@ -654,6 +674,14 @@ type WorkGrade struct {
 	Comment string    `json:"comment,omitempty"`
 }
 
+func (g *WorkGrade) Update() (*WorkGrade, error) {
+	if _, err := DBExec("UPDATE user_work_grades SET id_user = ?, id_work = ?, date = ?, grade = ?, comment = ? WHERE id_gradation = ?", g.IdUser, g.IdWork, g.Date, g.Grade, g.Comment, g.Id); err != nil {
+		return nil, err
+	} else {
+		return g, err
+	}
+}
+
 func (g WorkGrade) Delete() (int64, error) {
 	if res, err := DBExec("DELETE FROM user_work_grades WHERE id_gradation = ?", g.Id); err != nil {
 		return 0, err