add lokijs adapter to options in Context.ts

[jadvillafania]

New Pull Request Submissions:
Have you followed the guidelines in our Contributing document? Yes
Have you checked to ensure there aren't other open Pull Requests for the same update/change? Yes
I have added tests to cover my changes. No
All new and existing tests passed. Yes
Have you lint your code locally prior to submission? Yes
Does your code follows the code style of this project? Yes
Does your change require a change to the documentation. No
I have updated the documentation accordingly. --
Have you added an explanation of what your changes do and why you'd like us to include them? No
What kind of change does this PR introduce? (Bug fix, feature, docs update, ...) Feature

What is the current behavior? (You can also link to an open issue here)
Can not add LokiJs Adapter

What is the new behavior (if this is a feature change)?
Able to add LokiJs Adapter (such as LokiIndexedAdapter) to options object

Does this PR introduce a breaking change? (What changes might users need to make in their application due to this PR?) No

Other information: