added information how to install a package from a branch

README.md

@@ -2,6 +2,16 @@
 
 Install cdplib via pipenv: `pipenv install -e git+https://readonly:readonly@intra.acdp.at/gogs/tanja/cdplib.git#egg=cdplib  `
 
+
+#### Install via Pipfile
+
+* To install the master branch: Add to the \[packages\] section of the Pipfile the line:
+cdplib = {editable = true, git = "https://readonly:readonly@intra.acdp.at/gogs/tanja/cdplib.git"}
+
+* To install any other branch:
+cdplib = {editable = true, ref = "BRANCH", git = "https://readonly:readonly@intra.acdp.at/gogs/tanja/cdplib.git"}
+
+
 ### Adding new Features/Folders/Packages
 How to set up a new Package: