GitQlientPlugin is the project to build and integrated a QtCreator plugin of GitQlient
You can find the plugin in the release section. Once you have downloaded the plugin, copy it into the QtCreator folder where Qt is installed (Qt/Tools/QtCreator/lib/qtcreator/plugins) or in the following folders:
Linux
~/.local/share/data/QtProject/qtcreator/plugins/<version>
Windows
%LOCALAPPDATA%\QtProject\qtcreator\plugins\<version>
OSX
~/Library/Application Support/QtProject/Qt Creator/plugins/<version>
You need to replace with the QtCreator version (e.g. 4.10.2).
The plugin should be activated by default once you have copied it, so you just will need to reboot QtCreator.