old_contents: const env = process.env.NODE_ENV || 'development';
  
  const config = require('../config/config')[env];
  const fs = require('fs');
  const path = require('path');
  const Sequelize = require('sequelize');
  
  let sequelize;
  
  const basename = path.basename(module.filename);
  const db = {};
  
  if (config.use_env_variable) {
    sequelize = new Sequelize(process.env[config.use_env_variable]);
  } else {
    sequelize = new Sequelize(config.database, config.username, config.password, config);
  }
  
  function onlyJSFiles(file) {
    return (file.indexOf('.') !== 0) && (file !== basename) && (file.slice(-3) === '.js');
  }
  
  function importModel(file) {
    const model = sequelize.import(path.join(__dirname, file));
    db[model.name] = model;
  }
  
  function assignAssociations(modelName) {
    if (db[modelName].associate) {
      db[modelName].associate(db);
    }
  }
  
  fs
    .readdirSync(__dirname)
    .filter(onlyJSFiles)
    .forEach(importModel);
  
  Object.keys(db).forEach(assignAssociations);
  
  db.sequelize = sequelize;
  db.Sequelize = Sequelize;
  
  module.exports = db;
  
new_contents: 'use strict';
  
  var fs        = require('fs');
  var path      = require('path');
  var Sequelize = require('sequelize');
  var basename  = path.basename(module.filename);
  var env       = process.env.NODE_ENV || 'development';
  var config    = require(__dirname + '/../config/config.json')[env];
  var db        = {};
  
  if (config.use_env_variable) {
    var sequelize = new Sequelize(process.env[config.use_env_variable]);
  } else {
    var sequelize = new Sequelize(config.database, config.username, config.password, config);
  }
  
  fs
    .readdirSync(__dirname)
    .filter(function(file) {
      return (file.indexOf('.') !== 0) && (file !== basename) && (file.slice(-3) === '.js');
    })
    .forEach(function(file) {
      var model = sequelize['import'](path.join(__dirname, file));
      db[model.name] = model;
    });
  
  Object.keys(db).forEach(function(modelName) {
    if (db[modelName].associate) {
      db[modelName].associate(db);
    }
  });
  
  db.sequelize = sequelize;
  db.Sequelize = Sequelize;
  
  module.exports = db;
  
subject: Revert "Apply eslint feedback to models/index.js."