Pressing back twice to exit from dashboard

[sridharjajoo]

Summary:
When on the Dashboard when back is pressed we exit from the application.We could add a feature that when the user presses the back button once a toast is displayed asking whether he wants to exit and then he needs to again press the back button.

Steps to reproduce:
Go to dashboard and press back button.

I would like to work on this issue.

[RajaVamsi11]

@therajanmaurya Can I work on this issue?

[riyasingh1004]

Hi, I would like to work on this issue.