title: Field having multiple distinct values
body: <p>Am building a "Book search" API using Lucene.
  I need to index Book Name,Author, and Book category fields in Lucene index.</p>
  
  <p>A single book can fall under multiple distinct book categories...for example: </p>
  
  <p>BookName1 --fiction,humour,philosophy.
  BookName1 --fiction,science.
  BookName1 --humour,business.
  BookName4-humour
  and so on.....</p>
  
  <p>User should be able to search all the books under a particular category say "homour".</p>
  
  <p>Given this situation, how do i index above fields and build the query in lucene?</p>