installation issue

[zf480]

The terminal shows this when I performed "$ pip install git+https://github.com/quantstart/qstrader.git"

(qstraderp3) bash-3.2$ pip install git+https://github.com/quantstart/qstrader.git
Collecting git+https://github.com/quantstart/qstrader.git
Cloning https://github.com/quantstart/qstrader.git to /private/var/folders/h7/398y8n1d26d5qdcd6d11t2k80000gn/T/pip-req-build-r7y0ke4p
Running command git clone -q https://github.com/quantstart/qstrader.git /private/var/folders/h7/398y8n1d26d5qdcd6d11t2k80000gn/T/pip-req-build-r7y0ke4p
xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools), missing xcrun at:/Library/Developer/CommandLineTools/usr/bin/xcrun

ERROR: Command "git clone -q https://github.com/quantstart/qstrader.git /private/var/folders/h7/398y8n1d26d5qdcd6d11t2k80000gn/T/pip-req-build-r7y0ke4p" failed with error code 1 in None

May I know how I can possibly solve this problem?