Fix travel-sample to work on Python 3.7

Connecting to: couchbase://localhost/travel-sample?username=Administrator * Running on http://0.0.0.0:8080/ (Press CTRL+C to quit) 127.0.0.1 - - [15/Jan/2019 19:12:59] "GET / HTTP/1.1" 302 - 127.0.0.1 - - [15/Jan/2019 19:12:59] "GET /static/index.html HTTP/1.1" 200 - 127.0.0.1 - - [15/Jan/2019 19:13:00] "GET /static/assets/CBTravel.LOGO.png HTTP/1.1" 200 - 127.0.0.1 - - [15/Jan/2019 19:13:00] "GET /static/assets/poweredBy.01.png HTTP/1.1" 200 - [2019-01-15 19:13:06,733] ERROR in app: Exception on /api/user/signup [POST] Traceback (most recent call last): File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/flask/app.py", line 1982, in wsgi_app response = self.full_dispatch_request() File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/flask/app.py", line 1614, in full_dispatch_request rv = self.handle_user_exception(e) File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/flask/app.py", line 1517, in handle_user_exception reraise(exc_type, exc_value, tb) File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/flask/_compat.py", line 33, in reraise raise value File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/flask/app.py", line 1612, in full_dispatch_request rv = self.dispatch_request() File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/flask/app.py", line 1598, in dispatch_request return self.view_functions[rule.endpoint](**req.view_args) File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/flask_classy.py", line 200, in proxy response = view(**request.view_args) File "travel.py", line 183, in signup respjson = jsonify({'data': {'token': token}}) File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/flask/json.py", line 263, in jsonify (dumps(data, indent=indent, separators=separators), '\n'), File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/flask/json.py", line 123, in dumps rv = _json.dumps(obj, **kwargs) File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/json/__init__.py", line 238, in dumps **kw).encode(obj) File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/json/encoder.py", line 201, in encode chunks = list(chunks) File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/json/encoder.py", line 431, in _iterencode yield from _iterencode_dict(o, _current_indent_level) File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/json/encoder.py", line 405, in _iterencode_dict yield from chunks File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/json/encoder.py", line 405, in _iterencode_dict yield from chunks File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/json/encoder.py", line 438, in _iterencode o = _default(o) File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/flask/json.py", line 80, in default return _json.JSONEncoder.default(self, o) File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/json/encoder.py", line 179, in default raise TypeError(f'Object of type {o.__class__.__name__} ' TypeError: Object of type bytes is not JSON serializable 127.0.0.1 - - [15/Jan/2019 19:13:06] "POST /api/user/signup HTTP/1.1" 500 -