Connection options

[razvanc92]

Added options when creating the Mongo connection and if user/pass is provided then it will auth.

[eberhara]

@razvanc92 did you see the unit tests are failing?

  1) Mongration.Migration "before each" hook:
     Uncaught TypeError: Cannot read property 'pass' of undefined
      at MongoConnection.<anonymous> (src/utils/mongo-connection.js:26:24)
      at node_modules/mongodb/lib/mongo_client.js:406:11
      at _combinedTickCallback (internal/process/next_tick.js:73:7)
      at process._tickCallback (internal/process/next_tick.js:104:9)

Since options is not required, if(this.options.pass || this.options.user) will trigger that undefined on mongo-connection:26.

[razvanc92]

@eberhara I fixed the error. If you have any other comments/recommendations just let me know.