how to create unsigned apk

I am going answer my own question. I found solution.

UPDATE: I couldn't install apk bcoz unsigned apk cannot be install. For installing you have to sign it with certificate (debug or release).

In out/production folder apk is signed with debug key, its not unsigned.

If someone has a problem creating unsigned apk. here is the answer.

If you are using InteliJ IDEA or Android Studio.

https://www.jetbrains.com/idea/help/generating-an-unsigned-release-apk.html

If you are using eclipse use this

To export an unsigned APK from Eclipse, right-click the project in the Package Explorer and select Android Tools > Export Unsigned Application Package. Then specify the file location for the unsigned APK. (Alternatively, open your AndroidManifest.xml file in Eclipse, select the Manifest tab, and click Export an unsigned APK.)

With Ant

If you are using Ant, you can enable release mode by using the release option with the ant command. For example, if you are running Ant from the directory containing your build.xml file, the command would look like this:

$ ant release

By default, the build script compiles the application APK without signing it. The output file in your project bin/ will be -unsigned.apk.

http://developer.android.com/tools/publishing/app-signing.html