May need to make America/Detroit in cron config configurable

[jonespm]

Noticed this when I was reviewing the cron updates. I'm not sure if this is the same for other schools that might be hosted but this value that's used in the cron config should probably come from the django.conf settings.TIME_ZONE or a probably a new value to indicate the time zone in the database? There's 2 usages of this.

This looks like it was in the previous UDW config so it may not be an issue, or it might just not be one reported yet.

my-learning-analytics/config/cron_udp.hjson

Line 246 in 2fc6c4e

lar.posted_at at time zone 'America/Detroit' as grade_posted_local_date,

[cosimps]

Unizin supports making this configurable.

Currently, the Unizin hosted MyLA instances, both the django app and the cron, run with the America/Detroit timezone based on:

• https://github.com/tl-its-umich-edu/my-learning-analytics/blob/master/dockerfiles/Dockerfile#L75-L76
• setting of the TZ variable in our configs (ENV_FILE)

Unizin would prefer being able to set this via a config variable as it runs all of its hosted MyLA instances in the same cloud region that defaults the UTC time, so inheriting the timezone via a default compute method would not be ideal.

It appears as though the timezone setting is already configurable via both the TZ and TIME_ZONE variables.

It would be ideal for Unizin if the queries that MyLA runs respected those variables that are already being imported at runtime. Queries in question:

• https://github.com/tl-its-umich-edu/my-learning-analytics/blob/master/config/cron.hjson#L41
• https://github.com/tl-its-umich-edu/my-learning-analytics/blob/master/config/cron.hjson#L116
• https://github.com/tl-its-umich-edu/my-learning-analytics/blob/master/config/cron_udp.hjson#L110
• https://github.com/tl-its-umich-edu/my-learning-analytics/blob/master/config/cron_udp.hjson#L236

Also see #1484 as it pertains to this being computed correctly.

[pushyamig]

I changed the TZ value in .env to `"America/Chicago" and ran the cron, I see that assignment and submission tables where local data is present, it populated correct date based on timezone.

Test Pass