code: public void attachToGraph(GraphContext graphContext)
      {
          for (IssueCategory issueCategory : this.issueCategories.values())
          {
              IssueCategoryModel model = graphContext.create(IssueCategoryModel.class);
              model.setCategoryID(issueCategory.getCategoryID());
              model.setName(issueCategory.getName());
              model.setDescription(issueCategory.getDescription());
              model.setOrigin(issueCategory.getOrigin());
              model.setPriority(issueCategory.getPriority());
          }
      }
docs: Attaches all registered {@link IssueCategory}s to the graph. This allows them to be more easily used
  from rules.