Creating Debug/Release config for project

[UnickSoft]

Hi!
I want to have 2 configs for my project Debug and Release. The difference is in C++ flags. I tried to create separate makefile for release and call it, like:
make --f=Makefile_Release
But it doesn't work as expected. Make still uses Makefile. If I remove file Makefile, it outputs this:
make[1]: Nothing to be done for 'build'.

Can you please recommend me the way to split configurations?