Use JavaScript Standard Style

Introduce JavaScript Standard Style as project style rule,
and fixed all fail on backend code.

lib/models/author.js

@@ -1,43 +1,37 @@
-"use strict";
-
 // external modules
-var Sequelize = require("sequelize");
-
-// core
-var logger = require("../logger.js");
+var Sequelize = require('sequelize')
 
 module.exports = function (sequelize, DataTypes) {
-    var Author = sequelize.define("Author", {
-        id: {
-            type: Sequelize.INTEGER,
-            primaryKey: true,
-            autoIncrement: true
-        },
-        color: {
-            type: DataTypes.STRING
-        }
-    }, {
-        indexes: [
-            {
-                unique: true,
-                fields: ['noteId', 'userId']
-            }
-        ],
-        classMethods: {
-            associate: function (models) {
-                Author.belongsTo(models.Note, {
-                    foreignKey: "noteId",
-                    as: "note",
-                    constraints: false
-                });
-                Author.belongsTo(models.User, {
-                    foreignKey: "userId",
-                    as: "user",
-                    constraints: false
-                });
-            }
-        }
-    });
-    
-    return Author;
-};
+  var Author = sequelize.define('Author', {
+    id: {
+      type: Sequelize.INTEGER,
+      primaryKey: true,
+      autoIncrement: true
+    },
+    color: {
+      type: DataTypes.STRING
+    }
+  }, {
+    indexes: [
+      {
+        unique: true,
+        fields: ['noteId', 'userId']
+      }
+    ],
+    classMethods: {
+      associate: function (models) {
+        Author.belongsTo(models.Note, {
+          foreignKey: 'noteId',
+          as: 'note',
+          constraints: false
+        })
+        Author.belongsTo(models.User, {
+          foreignKey: 'userId',
+          as: 'user',
+          constraints: false
+        })
+      }
+    }
+  })
+  return Author
+}