Execute SOLR :
  Start Server.
  1.- Go to apache-solr-3.6.0/example/
  2.- Command : java -jar start-jar
  
  Add Json Document.
  1.- Go to apache-solr-3.6.0/example/exampledocs
  2.- Command : curl 'http://localhost:8983/solr/update/json?commit=true' 
                      --data-binary @filename.json -H 'Content-type:application/json'
  
  Remove all documents.
  1.- Go to apache-solr-3.6.0/example/exampledocs
  2.- Command : java -Ddata=args -jar post.jar "<delete><query>id:*</query></delete>"
  
  
  
Structure Data folder (for the interface):
  1 - data folder should be at the same level as src.
  2 - data
         |_ Universe1
         |_ Universe2
         |_ BowieState
            |_ pagerank 
                 |_ mentioned
                 |    |_ all
                 |    |    |_ PowerIteration.txt, MonteCarlo1.txt, ...  
                 |    |_ followers
                 |         |_ PowerIteration.txt, MonteCarlo1.txt, ... 
                 |_ retweeted

Authors: Jack Ha, Bernard Hernandez, Fernando J. Iglesias Garcia