[minor] Add button to add help article from Issue #7132 (#7154)

diff --git a/erpnext/support/doctype/issue/issue.js b/erpnext/support/doctype/issue/issue.js
index 21ef5b8..2bee422 100644
--- a/erpnext/support/doctype/issue/issue.js
+++ b/erpnext/support/doctype/issue/issue.js
@@ -15,5 +15,21 @@
 				frm.save();
 			});
 		}
+	},
+
+	timeline_refresh: function(frm) {
+		// create button for "Add to Knowledge Base"
+		if(frappe.model.can_create('Help Article')) {
+			$('<button class="btn btn-xs btn-default btn-add-to-kb pull-right" style="margin-top: -2px">'+
+				__('Add to Knowledge Base') + '</button>')
+				.appendTo(frm.timeline.wrapper.find('.comment-header'))
+				.on('click', function() {
+					var content = $(this).parents('.timeline-item:first').find('.timeline-item-content').html();
+					var doc = frappe.model.get_new_doc('Help Article');
+					doc.title = frm.doc.subject;
+					doc.content = content;
+					frappe.set_route('Form', 'Help Article', doc.name);
+				});
+		}
 	}
 });