Support django 2.1, DRF 3.9 and use django-filters > 2.0

[imomaliev]

• Added python 3.7 to travis and tox
• removed python2 from travis and tox
• Had to update postgres for travis to 9.4 and postgis to 2.4 because django 2.1 dropped support for 9.3

also fixes #170

Fails on python 2. Looks like I need to fix #171 as well. Can someone guide me so that I can drop python 2 support. What should be done I see multiple comments like

class GeoJsonDict(OrderedDict):
    """
    Used for serializing GIS values to GeoJSON values
    TODO: remove this when support for python 2.6/2.7 will be dropped
    """

Should GeoJsonDict be removed?

[auvipy]

do you think the pr could split up in several ones to handle the relevant issues in each one?

[imomaliev]

@auvipy I can't update packages separately, because they are dependent, but I could move addition of python 3.7 to travis and dropping of python 2 support in separate PRs

[nemesifier]

@imomaliev welcome and thanks for contributing.

1 question: why are you adding a Dockerfile and a docker-compose.yml?
We don't have enough resources to maintain those as things change, so if anyone tries to use it at some point in the future and it won't work, I personally won't have time to help them and will refer these users to you. Do you have time to maintain that over time? Consider this factor please, I'm not in favour of adding non essentials which need to be maintained by volunteers which are already over burdened.

[nemesifier]

@imomaliev welcome and thanks for contributing.

1 question: why are you adding a Dockerfile and a docker-compose.yml?
We don't have enough resources to maintain those as things change, so if anyone tries to use it at some point in the future and it won't work, I personally won't have time to help them and will refer these users to you. Do you have time to maintain that over time? Consider this factor please, I'm not in favour of adding non essentials which need to be maintained by volunteers which are already over burdened.

[imomaliev]

@nemesisdesign I do have time to maintain it. I would suggest having this in repo, because it simplifies setting up development environment for future contributors. But if you and other maintainers are so strongly against it, I will drop them from this PR

@auvipy So should I split this PR like I suggested in #173 (comment) ?

[imomaliev]

@nemesisdesign @auvipy ?

[nemesifier]

@imomaliev I'm not against having it, I just know that I won't be able to help if someone in the future reports that the docker image is not working.

Could you rebase your PR against the current master?

[imomaliev]

@nemesisdesign rebased

[nemesifier]

@imomaliev I was going to merge but after checking the code I found out something which looks like a minor issue, see below

[nemesifier]

Thanks @imomaliev @auvipy