minor change in new-grid-update

sails/roles/database/files/new-grid-system-adapt.sql

+-- Rename columns
+RENAME TABLE `scene` TO `grid`;
+ALTER TABLE `stu_picto` CHANGE `id_scene` `id_grid` int(11) NOT NULL;
+ALTER TABLE `student` CHANGE `id_active_scene` `id_active_grid` int(11) NULL;
+
+-- Add new column 'id_child_grid'
+ALTER TABLE `stu_picto` ADD `id_child_grid` int(11) NULL;
+
+-- Drop column 'categories'
+ALTER TABLE `grid` DROP COLUMN `categories`;
+
+-- Add color to grid column
+ALTER TABLE `grid` ADD `color` varchar(7) NULL;
+
+-- Foreign key stu_picto(id_child_grid) <- grid(id)
+ALTER TABLE stu_picto ADD FOREIGN KEY(id_child_grid) REFERENCES grid(id) ON DELETE SET NULL;
+
 DELIMITER $$
 DELIMITER $$
 
 
 DROP PROCEDURE IF EXISTS new_grid_system $$
 DROP PROCEDURE IF EXISTS new_grid_system $$