support youtube channels without vanity URLs, resolves #6

tubesync/sync/tests.py

@@ -35,6 +35,9 @@ class FrontEndTestCase(TestCase):
                 'valid': (
                     'https://www.youtube.com/testchannel',
                     'https://www.youtube.com/c/testchannel',
+                    'https://www.youtube.com/c/testchannel/videos',
+                    'https://www.youtube.com/channel/testchannel',
+                    'https://www.youtube.com/channel/testchannel/videos',
                 ),
                 'invalid_schema': (
                     'http://www.youtube.com/c/playlist',

tubesync/sync/views.py

@@ -157,7 +157,7 @@ class ValidateSourceView(FormView):
         Source.SOURCE_TYPE_YOUTUBE_CHANNEL: {
             'scheme': 'https',
             'domain': 'www.youtube.com',
-            'path_regex': '^\/(c\/)?([^\/]+)$',
+            'path_regex': '^\/(c\/|channel\/)?([^\/]+)(\/videos)?$',
             'path_must_not_match': ('/playlist', '/c/playlist'),
             'qs_args': [],
             'extract_key': ('path_regex', 1),