Send UTC TZ for mod creation timestamps

[HebaruSan]

Problem

As noted in Discord during review of KSP-CKAN/CKAN#3059, the timestamps from #195 don't indicate timezones. Technically this means they're in "local" time, whatever that means for a server/client interaction.

Cause

We just return created from the database, which is generated by datetime.now, which does not include the timezone:

SpaceDock/KerbalStuff/objects.py

Line 230 in 0e5f6c5

self.created = datetime.now()

It's not clear whether the timezone can be saved to the db anyway, though. At least one comment on StackExchange suggested it couldn't. So we can add it at load instead.

Changes

Now we set the TZ to UTC.

[Xinayder]

I feel like this is just a workaround. If we want to fix the problem, you should change

SpaceDock/KerbalStuff/objects.py

Line 230 in 0e5f6c5

self.created = datetime.now()

to datetime.utcnow() to return the UTC date.

Obviously it would apply to newly created mods only, so it would need your change as well to convert the current mods to UTC.

[HebaruSan]

@RockyTV are you sure that would save to the db? I saw reports that PostgreSQL doesn't save the TZ.

[DasSkelett]

Looks like Postgres would support timezones:

I think we could use it by changing this line to created = Column(DateTime(timezone=true)):

SpaceDock/KerbalStuff/objects.py

Line 349 in 0e5f6c5

created = Column(DateTime)

https://docs.sqlalchemy.org/en/13/core/type_basics.html#sqlalchemy.types.DateTime

This section also says the following, not sure what it means exactly:

For timezone support, use at least the TIMESTAMP datatype, if not the dialect-specific datatype object.

[HebaruSan]

@DasSkelett I think that's another branch, that line looks a bit different on alpha:

SpaceDock/KerbalStuff/objects.py

Line 305 in 67262ca

created = Column(DateTime, default=datetime.now)

... which goes back to the discussion about having to use a lambda. And I don't want to get into that with fourteen other instances of this for other fields in that ifle.

[DasSkelett]

Okay I see. Then let's stay with saving the local time (which fortunately is UTC), and converting it when handing it out via API, as your PR does currently.

If we want to, we can clean this up later, all instances of this at once, with a data migration and so on.

[DasSkelett]

Let's try it. Not 100% sure if netkan will convert +00:00 to Z to match mods from other APIs, but I think so.
We should give it a try.