shunchu

t = 236 # seconds
Time.at(t).utc.strftime("%H:%M:%S")
=> "00:03:56"

# Reference
# http://stackoverflow.com/questions/3963930/ruby-rails-how-to-convert-seconds-to-time

vasanthk

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

1. Clarify and agree on the scope of the system

• User cases (description of sequences of events that, taken together, lead to a system doing something useful)
  • Who is going to use it?
  • How are they going to use it?

Kartones

PSQL

Magic words:

psql -U postgres

Some interesting flags (to see all, use -h or --help depending on your psql version):

• -E: will describe the underlaying queries of the \ commands (cool for learning!)
• -l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)

indiesquidge

Homebrew

How To

Homebrew is a package management system for OS X. You can read more about it here, or simply run

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

to install it.

gaearon

If you haven’t worked with JavaScript in the last few years, these three points should give you enough knowledge to feel comfortable reading the React documentation:

• We define variables with let and const statements. For the purposes of the React documentation, you can consider them equivalent to var.
• We use the class keyword to define JavaScript classes. There are two things worth remembering about them. Firstly, unlike with objects, you don't need to put commas between class method definitions. Secondly, unlike many other languages with classes, in JavaScript the value of this in a method [depends on how it is called](https://developer.mozilla.org/en-US/docs/Web/Jav

lucasfais

Sublime Text 2 – Useful Shortcuts (Mac OS X)

General

⌘T	go to file
⌘⌃P	go to project
⌘R	go to methods
⌃G	go to line
⌘KB	toggle side bar
⌘⇧P	command prompt

dhh

ruby '2.7.1'

gem 'rails', github: 'rails/rails'
gem 'tzinfo-data', '>= 1.2016.7'  # Don't rely on OSX/Linux timezone data

# Action Text
gem 'actiontext', github: 'basecamp/actiontext', ref: 'okra'
gem 'okra', github: 'basecamp/okra'

# Drivers

tsrivishnu

Git: How can I ignore a file that is already committed to the repo?

You have a repo and quite some developers have cloned the repo and working on it. Now you want to add a file to gitignore which is already checked-in or tracked by Git.(The file is already commited into the repo)

Below are the steps on how to ignore this file (lets say the filename is config.py):

• Add it to .gitignore:

$ echo "config.py" >> .gitignore

cblunt

# ...

gem 'carrierwave'
gem 'fog', '~> 1.0.0' # Need to specify version, as carrierwave references older (0.9.0) which doesn't allow configuration of Rackspace UK Auth URL

rwarbelow

1. Add gem 'rails_12factor' to your Gemfile. This will add error logging and the ability for your app to serve static assets.
2. bundle
3. Run RAILS_ENV=production rake db:create db:migrate db:seed
4. Run rake secret and copy the output
5. From the command line: export SECRET_KEY_BASE=output-of-rake-secret
6. To precompile your assets, run rake assets:precompile. This will create a folder public/assets that contains all of your assets.
7. Run RAILS_ENV=production rails s and you should see your app.

Remember to clobber your assets (rake assets:clobber) and re-precompile (rake assets:precompile) if you make changes.