TIL, 2017-05-23

Ajax collapsing json data. Go figure.
Puma, then Passenger, then Unicorn.
SuckerPunch doesn’t need anything else (Redis, db) so you can use it for logging stuff.
Delayed::Job uses a database table to store the jobs.
Sidekiq is faster than Delayed::Job.
2017 Rails Stack: Ruby 2.3, Rails 5 (or Rails 4.2 + Ruby 2.3), Postgres, Redis/Memcache/ElasticSearch over MongoDB/Solr, Sidekiq over Delayed::Job/Resque, Puma over Unicorn/Passenger. Reference
top command: Displays processor activity of your Linux box and also displays tasks managed by the Kernel.
cron-apt: Automating apt via cron which gets updates.
sudo su.
Staging: Snapshots.
ssh ubuntu@oprivate-ip-of-nginx -i path/to/pemfile.pem.
usermod.
libpg-dev: Only needed by postgres
rake secret
secret_key_base: Used to verify the integrity of signed cookies for the app.
cut: You can do this like gem list | cut -d ' ' -f1 which means from the gem list, you split via delimiter ` `, then get the first element of the array.