Show colors at the top of the colorbar when creating a gantt with custom colors

Author: omridanan

Diff for: plotly/figure_factory/_gantt.py

@@ -502,6 +502,7 @@ def gantt_dict(chart, colors, title, index_col, show_colorbar, bar_width,
         entry = dict(
             x=[tasks[index]['x0'], tasks[index]['x1']],
             y=[groupID, groupID],
+            showlegend=False,
             name='',
             marker={'color': 'white'}
         )

Diff for: plotly/tests/test_optional/test_tools/test_figure_factory.py

@@ -1351,26 +1351,31 @@ def test_gannt_groups_and_descriptions(self):
         exp_gantt_chart = {
             'data': [{'marker': {'color': 'white'},
                'name': '',
+               'showlegend': False,
                'text': 'Task A - 1',
                'x': ['2008-10-05', '2009-04-15'],
                'y': [2, 2]},
               {'marker': {'color': 'white'},
                'name': '',
+               'showlegend': False,
                'text': 'Task B - 1',
                'x': ['2008-12-06', '2009-03-15'],
                'y': [1, 1]},
               {'marker': {'color': 'white'},
                'name': '',
+               'showlegend': False,
                'text': 'Task C - 1',
                'x': ['2008-09-07', '2009-03-15'],
                'y': [0, 0]},
               {'marker': {'color': 'white'},
                'name': '',
+               'showlegend': False,
                'text': 'Task C - 2',
                'x': ['2009-05-08', '2009-04-15'],
                'y': [0, 0]},
               {'marker': {'color': 'white'},
                'name': '',
+               'showlegend': False,
                'text': 'Task A - 2',
                'x': ['2009-04-20', '2009-05-30'],
                'y': [2, 2]},