Google store says Ready to Publish
Op's feedback:
Press Mange Releases Button -- > Then go to the bottom of the page --> Click Review Button.After that Publish button will be shown.
Original Answer:
It's similar to App store, Your application need to be accepted by tester for review and install on different device. "Ready to publish" does not mean you can publish it globally unless you define internal or external (Alpha/Beta)tester, and those how choose to install your app need to review your app.
https://support.google.com/googleplay/android-developer/answer/3131213?hl=en
Good Luck
The accepted answer is now outdated.
On left side menu select 'Publishing overview'.
Click on 'Review and publish'.
Approve publish.
By the way, this is happening because you've turned on 'Managed publishing status'. I recommend leaving it on, as it lets control when your app will actually be published after Google's review.
