add docs for new feature
add docs for new feature

peteychuk/react-native-router-flux,gijoehosaphat/react-native-router-flux,Wondermall/react-native-router-flux,gijoehosaphat/react-native-router-flux,gectorat/react-native-router-flux,Wondermall/react-native-router-flux,aksonov/react-native-router-flux,gectorat/react-native-router-flux,gectorat/react-native-router-flux,charpeni/react-native-router-flux,hungtn/react-native-router-flux,charpeni/react-native-router-flux,dmazin/react-native-router-flux,Swordsman-Inaction/react-native-router-flux,dmazin/react-native-router-flux,Swordsman-Inaction/react-native-router-flux,gijoehosaphat/react-native-router-flux,peteychuk/react-native-router-flux,r0b1n/react-native-router-flux,Wondermall/react-native-router-flux,hungtn/react-native-router-flux,dmazin/react-native-router-flux,charpeni/react-native-router-flux,mcabs3/react-native-router-flux,r0b1n/react-native-router-flux,Swordsman-Inaction/react-native-router-flux,mcabs3/react-native-router-flux,peteychuk/react-native-router-flux,mcabs3/react-native-router-flux