It is a common misunderstanding that all [op]=-operators work the same way, but actually they don't. ||= and &&=

When using send_file (for example for attachments of any kind), make sure your application knows the correct mime types...

You can freeze any Ruby object to prevent further modification. If you freeze an ActiveRecord and try to set an...

Rails comes with a Rake task notes that shows code comments that start with "TODO", "FIXME", or "OPTIMIZE".

In RSpec you can tag examples or example groups with any tags you like simply by saying describe ReportCreator, slow...

If you want to grow a Ruby Array, you might find out about #fill but it is not really what...

Code folding is a very useful feature to me. It gives me a quick overview over a file and keeps...

# Given the following models class Image < ActiveRecord::Base has_many :album_images has_many :albums, through: :album_images

To use a form model with devise, you can simply override #resource_class in a controller. A typical use case...

Fontawesome 4 ships with many useful CSS helper classes. Enlarge Icon Add fa-lg (133%), fa-2x, fa-3x, fa...

Starting from Rails 4.0, you can use a special form options helper called #collection_check_boxes. It behaves similar to...

When using threads, you must make your code thread-safe. This can be done by either locking (mutexes) all data...

When ending a Selenium test Capybara resets the browser state by closing the tab, clearing cookies, localStorage, etc.

There are some frontends available, but they all suck, are no longer maintained or are hard to install.

You know that ActiveRecord caches associations so they are not loaded twice for the same object. You also know that...

Instead of this: Image.order('images.created_at DESC') You can write this: Image.order(created_at: :desc) Not only do you not...

It's generally not trivial to change a datetime's seconds, minutes, etc in SQL. Here is how it works...

Today I learned that Ruby on Rails has shipped with a built-in slug generator since Rails 2.2:

Web applications can be used by multiple users at the same time. A typical application server like Passenger has multiple...

RSpec 3 has verifying doubles. This breed of mock objects check that any methods being stubbed are present on an...

If you need to log to a file you can use Ruby's Logger class: require 'logger'

Here's a pretty useful steps that hasn't made it into Spreewald yet. It is best used with the...