add class diagram as image

[VladimirAlexiev]

most people cannot read https://github.com/Ontotext-AD/graphdb.js/blob/master/model/rdf4js.xmi.
So please add the class diagram also as an image.

Better yet, redo it in Plantuml; I can help.

cc @desislava-hristova-ontotext

[ThirumlaDevi]

@VladimirAlexiev I have made simple class diagrams using Plantuml before, but I think I can help you with this cause the documentation of the tool is pretty good. Could you please let me know if there are any instructions on how to generate the class diagram from the xmi file ? I tried to do the same via draw.io tool, but that failed too.

[VladimirAlexiev]

@ThirumlaDevi you need to open it in a UML editor like EA.
I've tried opening XMI (though not this particular one) in the free StarUML but failed.