NestedNavigators in stacknavigator not work

[hari-mohan-choudhary]

branch NestedNavigators face issue in tab navigation in add stacknavigation is not working proper so how use ?

`export const Profile = StackNavigator({
addpeople: {
screen: peopleScreen
},
removepeople: {
screen: RemovePeopleScreen
}
});

export const Tabs = TabNavigator({
Explore: {
screen: Explore
},
booking: {
screen: BookingScreen
},
Status: {
screen: StatusScreen,
},
WishpointView: {
screen: Wishpoint,
},

logout: {
screen: Logout,
navigationOptions: {
tabBarLabel: "Logout",
title: "Logout"
}
}
});

const navigator = StackNavigator({
login: {
screen: Login
},
signup: {
screen: Signup
},
mainScreens: {
screen: Tabs,
navigationOptions: {
gesturesEnabled: false,
headerLeft: null
}
}
});

export default navigator;`