add: get similarity result among documents for description based on TermVector

Calculating scores among documents for description and making lists to show
the results of scores from each quries.

Reference:
a. brief presentation about Lucene scoring: http://goo.gl/4DK6Xz
b. Scoring - Introduction (lucene.apache.org): http://goo.gl/mrGWjr
c. Class MOreLikeThisQuery: http://goo.gl/5ihPpa

TODO: need to consider different Scoring methods if I can
update README.md: understanding Lucene scoring