improve the README
improve the README

lichia/cassandra-reaper,eBayClassifiedsGroup/cassandra-reaper,lichia/cassandra-reaper,mkolla01/repair,mjager/cassandra-reaper,colinkuo/cassandra-reaper,gnoremac/cassandra-reaper,gnoremac/cassandra-reaper,garo/cassandra-reaper,lichia/cassandra-reaper,garo/cassandra-reaper,Yarin78/cassandra-reaper,garo/cassandra-reaper,Yarin78/cassandra-reaper,thelastpickle/cassandra-reaper,Nuance-Mobility/cassandra-reaper,Nuance-Mobility/cassandra-reaper,eBayClassifiedsGroup/cassandra-reaper,thelastpickle/cassandra-reaper,eBayClassifiedsGroup/cassandra-reaper,eBayClassifiedsGroup/cassandra-reaper,gnoremac/cassandra-reaper,thelastpickle/cassandra-reaper,thelastpickle/cassandra-reaper,mjager/cassandra-reaper,Nuance-Mobility/cassandra-reaper,mjager/cassandra-reaper,thelastpickle/cassandra-reaper,mkolla01/repair,gnoremac/cassandra-reaper,Yarin78/cassandra-reaper,colinkuo/cassandra-reaper,mkolla01/repair,colinkuo/cassandra-reaper