I just migrated my Eclipse projects to IntelliJ IDEA (it's the same as AndroidStudio uses, but with some minor differences).
However every time I click Build > Build Apk it generates an APK with "debug enabled".
What I've been reading the android:debuggable="true" property has not been supported since 2010.
How can I generate the APK?
I think the "no debugger" mode is only when the app is signed, so you have an .apk to send to the play store. You can not send an app to the store without it being signed (which gives it as a debugger).
Create a signature for it and link to the project there:
Right click on Project:
Open Module Settings > Signing
Add a signature and link the .jks file at this point your project will be signed and you can release the users, to return to development, remove the signature and later turn it back on, when you release a new realese.