Previously, we would initialize an ImageOptim object each time we resize.
This object init is mega expensive (170ms on a VERY fast machine):
```
[1] pry(main)> Benchmark.measure { FileHelper.image_optim }
=> #<Benchmark::Tms:0x00007f55440c1de0
@cstime=0.055742,
@cutime=0.141031,
@label="",
@real=0.17165619300794788,
@stime=0.0002750000000000252,
@total=0.19890400000000008,
@utime=0.0018560000000000798>
```
This happens cause during init it hunts for all the right binaries and sets
up internals.
We now memoize this object to avoid a huge amount of pointless work.
Previously we depended on non Sidekiq specific mocking which is not the
official way of testing Sidekiq, this made these tests very fragile
New testing is more robust and complete
This ensures that unicorn master forks of sidekiq run with a lower priority
than the webs. It means that a busy sidekiq is less likely to impact web
performance
This allows us to run regular rebakes without starving the normal queue.
It additionally adds the ability to specify queue with `Jobs.enqueue` so
we can specifically queue a job with lower priority using the `queue` arg.
Previously we killed caching on old avatars cause we kept serving blank
this meant we would front many more avatar requests after a version change
This change ensures all old avatars do not cause a flood of requests on the
server
We query this table when getting composer messages with the queries
such as:
```
SELECT 1 AS one FROM "user_histories"
WHERE "user_histories"."target_user_id" = 1 AND
"user_histories"."action" = 9 AND
"user_histories"."topic_id" = 105794
LIMIT 1
```
This index ensures this query remains very quick, regardless of user
history size.
Before this patch, a high trust level user could flag something
and have an action be taken, as well as skipping the flag queue.
Now, if a TL3/TL4 cause an action, the flag will skip the minimum
visibility check and allow staff to review it.
FIX: buildTranslationTree was erroring when translations overlapped (ie. ":-)" and ":-))")
FIX: emoji translations wasn't working properly when translations overlapped
