sign apk

➜  Android git:(feature/continue_bugfix4old) ✗ adb install Android.apk
3744 KB/s (2424953 bytes in 0.632s)
pkg: /data/local/tmp/Android.apk
Failure [INSTALL_FAILED_ALREADY_EXISTS]

If you install the application on your device via adb install you should look for the reinstall option which should be -r. So if you do adb install -r you should be able to install without uninstalling before.

➜  Android git:(feature/continue_bugfix4old) ✗ adb install -r Android.apk
3668 KB/s (2424953 bytes in 0.645s)
pkg: /data/local/tmp/Android.apk
Failure [INSTALL_PARSE_FAILED_INCONSISTENT_CERTIFICATES]