add visible property to announcement

server/api/models/announcement.js

@@ -1,7 +1,8 @@
 module.exports = (sequelize, DataTypes) => {
   const announcement = sequelize.define('announcement', {
     announce: DataTypes.STRING,
-    until: DataTypes.DATE
+    until: DataTypes.DATE,
+    visible: DataTypes.BOOLEAN
   }, {})
 
   return announcement

server/migrations/20200215153310-create-announcement.js

@@ -13,6 +13,7 @@ module.exports = {
       until: {
         type: Sequelize.DATE
       },
+      visible: Sequelize.BOOLEAN,
       createdAt: {
         allowNull: false,
         type: Sequelize.DATE