Update representatives to include chambers data migration

setup.py

@@ -16,7 +16,7 @@ setup(name='political-memory',
         'django-datetime-widget>=0.9,<1.0',
         'django-filter>=0.11,<0.12',
         'django-representatives-votes==0.0.15',
-        'django-representatives==0.0.18',
+        'django-representatives==0.0.19',
         'django-taggit>=0.17,<0.18',
         'django>=1.8,<1.9',
         'djangorestframework>=3.2.0,<3.3.0',