Improve comments on state.js

Author: Claudio Ludovico Panetta

src/store/states.js

@@ -4,12 +4,16 @@ export const state = {
      * Each time a photo is selected from
      * the gallery this property became a
      * Photo Object
+     * 
+     * @type {Object}
      */
     selectedPhoto: {},
 
     /**
      * List of photos available inside
      * the gallery.
+     * 
+     * @type {Array}
      */
     photos: []
 };