macos app informations in README

Author: stfbnc

README.md

@@ -2,5 +2,7 @@
 `FATool` is an app (macOS and Ubuntu) for detrended fluctuations analysis and related algorithms, and plots of the results.
 ## macOS
 
+Download `fatool.dmg` and copy `FATool.app` in your `Application` folder.
+
 ## Ubuntu
 Download `fatool.tar.gz`, untar it, enter `fatool` directory and run `install.sh`. You can then launch the application with the `FATool` command.