How to compile this?

I tried to compile/build this using Android Studio, but ended up with an error.
app/build.gradle (1error)
No .git directory found!

I tried to compile this using 2 different machine. One with Android Studio under Windows 10 and another on Linux. I'm getting the same error on different machine.

How to fix this?

[Azazel]

Can you please download the source code using git clone not using "Download .zip" button. This way you will have .git folder and it should properly compile.