mongoose connection util (with model look up and drop collections)

database.js

'use strict';
var mongoose = require('mongoose');
var config = require('../config/database.json');
var database = null;
var RSVP = require('rsvp');

module.exports = {
  init: function(envSt) {
    if (database == null) {
      var env = config[envSt];
      var rsvp = new RSVP.Promise(function(resolve, reject){
        mongoose.connection.on('open', function(){
          console.log("connecting to " + env.host + " at " + env.port + " on " + env.databaseName + " with " + JSON.stringify(env.serverOptions));
          resolve();
        });
        mongoose.connection.on('error', function(err){
          reject(err);
        });
      });
      database = mongoose.connect('mongodb://' + env.host + ':' + env.port + '/' + env.databaseName, env.serverOptions);
      return rsvp;
    }
  },
  model: function(modelName) {
    // return mongoose.model(model_name, eval("" + model_name + "_model"));
    var requireSt = './models/' + modelName;
    return mongoose.model(modelName, require(requireSt));
  },
  drop: function(){
    var currentEnv = require('./currentEnv');
    var dropCollections = [];
    var rsvp = null;
    if(currentEnv.get() !== 'production'){
      rsvp = new RSVP.Promise(function(resolve, reject){
        database.connection.db.collections(function (err, collections) {
          var todo = collections.length;
          if(todo === 0){
            resolve();
          }
          collections.forEach(function(collection){
            if(!collection.collectionName.match(/^system\./)){
              collection.remove({},{safe: true},function(){
                console.log('removing collection', collection.collectionName);
                if (--todo === 0) {
                  resolve();
                }
              });
            }else{
              if (--todo === 0) {
                resolve();
              }
            }

          });
        });
      });
    }
    return rsvp;
  },
  close: function() {
    var rsvp = new RSVP.Promise(function(resolve, reject){
      database.connection.on('close', function(){
        resolve();
      });
    });
    database.connection.close();
    return rsvp;
  }
};