Add paragraphs in README on how to configure cluster and replication.
Add paragraphs in README on how to configure cluster and replication.

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nrk/predis,SecureCloud-biz/predis,zhangyancoder/predis,mrkeng/predis,protomouse/predis,moria/predis,CloudSide/predis,SwelenFrance/predis,gopalindians/predis,johnhelmuth/predis,stokes3452/predis,oswaldderiemaecker/predis,quangnguyen90/predis,lvbaosong/predis,WalterShe/predis,gencer/predis,vend/predis,dzung2t/predis,RudyJessop/predis,nguyenthaihan/predis