Translated 21a-Text_Searches_in_MongoDB-Lecture. Closes #399
Updated according to feedback
Merge pull request #429 from jcarlosgarcia/issue-399

Translated 21a-Text_Searches_in_MongoDB-Lecture. Closes #399
Fixed issues with JSON mapping for Week 5.
Merge pull request #430 from juancarlosfarah/master

Fixed issues with JSON mapping for Week 5.