Added git command for 2.8 branch

Using-Blendercam-from-github.md

@@ -27,7 +27,7 @@ On Debian/Ubuntu, these can be installed with `apt install python3-shapely pytho
 ## Get Blendercam source code
 The first step is to get the source code from the github repository.
  1. Assuming that Git is installed on your machine, at the command prompt change into the directory where blendercam will be and then type:
- 2. `git clone https://github.com/vilemnovak/blendercam.git`
+ 2. `git clone https://github.com/vilemnovak/blendercam.git` or for Blender 2.8 `git clone --branch 2.80_BETA https://github.com/vilemnovak/blendercam.git`
 
  ![git clone](https://cloud.githubusercontent.com/assets/648108/12068782/8942a84a-afeb-11e5-86c4-31a60475fd27.png)