Due to issue #482 Highcharts can not be loaded automatically from Github.
To install it execute the following steps:
1- Clone https://github.com/brunobuzzi/HighchartsSt
Switch to branch: v6.0.1
$ git checkout v6.0.1
2- Inside GemStone/S execute the following code:
GsDeployer deploy: [Metacello newconfiguration: 'HighchartsSt';version: #stable;repository: 'filetree://$GS_HOME/shared/repos/HighchartsSt/';onLock: [:ex | ex honor];load.].
Where $GS_HOME is the path of GsDevKit installation. For example $GS_HOME could be /home/gemstone/GsDevKit_home where gemstone is the Linux username.