Added link for Cop:Rails in contributing.md
Added link for Cop:Rails in contributing.md

rishabhptr/osem,kormoc/osem,namangupta01/osem,SeaGL/osem,BelieveC/osem,BelieveC/osem,BelieveC/osem,openSUSE/osem,kormoc/osem,differentreality/osem,SeaGL/osem,hennevogel/osem,hennevogel/osem,rishabhptr/osem,rishabhptr/osem,bear454/osem,hennevogel/osem,AndrewKvalheim/osem,hennevogel/osem,differentreality/osem,openSUSE/osem,AndrewKvalheim/osem,kormoc/osem,differentreality/osem,bear454/osem,namangupta01/osem,rishabhptr/osem,namangupta01/osem,differentreality/osem,BelieveC/osem,bear454/osem,namangupta01/osem,kormoc/osem,SeaGL/osem,bear454/osem,openSUSE/osem,AndrewKvalheim/osem