Refactor(main): Redefine method calls to use this
Refactor(main): Redefine method calls to use this

Redefine createIndex method calls
Redefine readTexts method calls
Redefine searchKeys to check for null and {}
Restrict readTexts to take JSON file (objects) only
Remove debugging statements
include delimeter in .join

andela-batolagbe/inverted-index,andela-batolagbe/inverted-index