combinatorics/partitions: Added routine to rank a RGS.
combinatorics/partitions: Added routine to rank a RGS.

Signed-off-by: Saptarshi Mandal <13ec3c7bab52575f3a0cda6406c76269cc13b041@gmail.com>

emon10005/sympy,Designist/sympy,kmacinnis/sympy,wanglongqi/sympy,hrashk/sympy,sunny94/temp,wyom/sympy,saurabhjn76/sympy,kaichogami/sympy,maniteja123/sympy,vipulroxx/sympy,VaibhavAgarwalVA/sympy,skidzo/sympy,Gadal/sympy,abhiii5459/sympy,sahmed95/sympy,jamesblunt/sympy,cccfran/sympy,sunny94/temp,farhaanbukhsh/sympy,postvakje/sympy,grevutiu-gabriel/sympy,ahhda/sympy,liangjiaxing/sympy,AkademieOlympia/sympy,hargup/sympy,mafiya69/sympy,Sumith1896/sympy,sahmed95/sympy,kaushik94/sympy,atreyv/sympy,wyom/sympy,amitjamadagni/sympy,Shaswat27/sympy,VaibhavAgarwalVA/sympy,AkademieOlympia/sympy,jerli/sympy,kumarkrishna/sympy,bukzor/sympy,debugger22/sympy,jbbskinny/sympy,chaffra/sympy,srjoglekar246/sympy,garvitr/sympy,Sumith1896/sympy,maniteja123/sympy,kmacinnis/sympy,sahilshekhawat/sympy,dqnykamp/sympy,atsao72/sympy,dqnykamp/sympy,liangjiaxing/sympy,kaichogami/sympy,pandeyadarsh/sympy,amitjamadagni/sympy,drufat/sympy,abloomston/sympy,MechCoder/sympy,Vishluck/sympy,lidavidm/sympy,beni55/sympy,chaffra/sympy,yashsharan/sympy,shikil/sympy,asm666/sympy,wanglongqi/sympy,pbrady/sympy,skidzo/sympy,emon10005/sympy,rahuldan/sympy,yukoba/sympy,Curious72/sympy,iamutkarshtiwari/sympy,pandeyadarsh/sympy,oliverlee/sympy,kevalds51/sympy,debugger22/sympy,shikil/sympy,iamutkarshtiwari/sympy,Arafatk/sympy,Gadal/sympy,madan96/sympy,jbbskinny/sympy,souravsingh/sympy,Titan-C/sympy,asm666/sympy,saurabhjn76/sympy,sunny94/temp,AkademieOlympia/sympy,ga7g08/sympy,shipci/sympy,Davidjohnwilson/sympy,cswiercz/sympy,shipci/sympy,AunShiLord/sympy,jaimahajan1997/sympy,lindsayad/sympy,dqnykamp/sympy,drufat/sympy,MechCoder/sympy,Titan-C/sympy,meghana1995/sympy,bukzor/sympy,Shaswat27/sympy,kmacinnis/sympy,lindsayad/sympy,hrashk/sympy,wanglongqi/sympy,aktech/sympy,souravsingh/sympy,grevutiu-gabriel/sympy,Mitchkoens/sympy,Mitchkoens/sympy,kaichogami/sympy,drufat/sympy,cswiercz/sympy,kaushik94/sympy,maniteja123/sympy,mcdaniel67/sympy,debugger22/sympy,moble/sympy,pandeyadarsh/sympy,liangjiaxing/sympy,lidavidm/sympy,rahuldan/sympy,ChristinaZografou/sympy,ChristinaZografou/sympy,vipulroxx/sympy,skirpichev/omg,Shaswat27/sympy,ga7g08/sympy,Gadal/sympy,Mitchkoens/sympy,meghana1995/sympy,skidzo/sympy,madan96/sympy,saurabhjn76/sympy,kumarkrishna/sympy,Titan-C/sympy,yashsharan/sympy,beni55/sympy,jerli/sympy,sampadsaha5/sympy,sahilshekhawat/sympy,MridulS/sympy,diofant/diofant,kevalds51/sympy,lindsayad/sympy,jamesblunt/sympy,jaimahajan1997/sympy,toolforger/sympy,moble/sympy,chaffra/sympy,garvitr/sympy,jaimahajan1997/sympy,asm666/sympy,pbrady/sympy,meghana1995/sympy,aktech/sympy,kaushik94/sympy,shikil/sympy,souravsingh/sympy,lidavidm/sympy,Designist/sympy,atsao72/sympy,cswiercz/sympy,AunShiLord/sympy,AunShiLord/sympy,sahilshekhawat/sympy,toolforger/sympy,postvakje/sympy,kumarkrishna/sympy,postvakje/sympy,yukoba/sympy,MechCoder/sympy,rahuldan/sympy,sampadsaha5/sympy,Curious72/sympy,atsao72/sympy,Sumith1896/sympy,pbrady/sympy,vipulroxx/sympy,wyom/sympy,ChristinaZografou/sympy,yashsharan/sympy,oliverlee/sympy,cccfran/sympy,farhaanbukhsh/sympy,VaibhavAgarwalVA/sympy,emon10005/sympy,atreyv/sympy,Vishluck/sympy,mafiya69/sympy,ahhda/sympy,cccfran/sympy,mcdaniel67/sympy,abhiii5459/sympy,Vishluck/sympy,Davidjohnwilson/sympy,mafiya69/sympy,hargup/sympy,abloomston/sympy,bukzor/sympy,madan96/sympy,hrashk/sympy,moble/sympy,oliverlee/sympy,Arafatk/sympy,toolforger/sympy,garvitr/sympy,grevutiu-gabriel/sympy,sampadsaha5/sympy,MridulS/sympy,jamesblunt/sympy,Davidjohnwilson/sympy,iamutkarshtiwari/sympy,mcdaniel67/sympy,Arafatk/sympy,hargup/sympy,jerli/sympy,abloomston/sympy,abhiii5459/sympy,shipci/sympy,kevalds51/sympy,MridulS/sympy,Designist/sympy,Curious72/sympy,ga7g08/sympy,atreyv/sympy,beni55/sympy,farhaanbukhsh/sympy,aktech/sympy,sahmed95/sympy,jbbskinny/sympy,ahhda/sympy,flacjacket/sympy,yukoba/sympy