Don't say is_a?(ActiveRecord::NamedScope::Scope) because that is no longer true in Rails 3 and also doesn't match unscoped ActiveRecord classes themselves (which we consider scopes for all practical purposes).

A good way is to say this instead:

object.respond_to?(:scoped)

If you want to update some records with boolean fields in a migration, always remember to set your values with field=#{quoted_true} and field=#{quoted_false}. The Rails methods quoted_false and quoted_true return the correct boolean representations for your database.

Usually, Cucumber feature files live in features/. When you group them in sub directories, make sure to add -r features to the standard Cucumber options.

In Rails apps, Cucumber options are likely to be stored in config/cucumber.yml.

When you include a non-existing Javascript file, you probably won't notice it during development. But with caching active (on production or staging) Rails will write an empty all.js file without complaining.

Free Bootstrap theme resembling Material Design.

Bootswatch offers Sass and Less files, so the theme can easily be integrated into your usual Rails application.

Implements only Bootstrap features which means that some Material stuff is missing, but also that you can easily use or replace the theme.
Does not come with extra JavaScript; some effects like button click ripples are implemented via CSS.

Also check out their other themes which can be used in a similar fashion.

Use Traim to build a RESTful API for your ActiveRecord models with very little code.

Traim assumes your API resources will map 1:1 to your ActiveRecord models and database tables. This assumption usually falls apart after a few months into a project, so be ready to replace your Traim API with something more expressive afterwards.

Traim outputs a Rack application which you can either serve standalone or mount into your Rails app.

This finally works:
User.any_instance.should_receive(...)
as does
User.any_instance.stub(...)

Note: You won't have RSpec 2.6 if you're still working on Rails 2.

This is what worked for me in a Rails 4:

# JSON data as first argument, then parameters
patch :update, { some: 'data' }.to_json, id: id, format: :json

Ruby 1.9.2 is very slow when loading files, especially starting Rails servers or running specs takes forever.

Do yourself a favor and upgrade to 1.9.3.

This will give you the string that appears most often in an array:

names = %w[ foo foo bar bar bar baz ]
names.group_by(&:to_s).values.max_by(&:size).try(:first)
=> "bar"

This is very similar to the linked StackOverflow thread, but does not break on empty arrays.

Note that try is provided by ActiveSupport (Rails). You could explicitly load activesupport or use andand on plain Ruby.

If you specify different ports, you can run multiple local webricks with rails server --port=300X at the same time.

If you were using Dusen for its query parsing and LIKE queries, we recommend to migrate to Minidusen, which extracts those parts from Dusen. Minidusen is compatible with MySQL, PostgreSQL and Rails 3.2, 4.2 and 5.0.

If you are looking for a full text indexing solution, we recommend to use PostgreSQL with pg_search.

When there's a Gemfile.lock in your working directory that you cannot remove by either checkout, reset [--hard], stash, probably Rails' Spring is the culprit and not Bundler itself.

Fix

spring stop

The author of the linked Stackoverflow post supposes Spring re-writes the Gemfile.lock on change to ensure all Spring processes are using the same gem versions. Meh.

Lightweight Angular JS directive to upload files

Includes polyfills for old IEs. Unfortunately, their auto-loading mechanism may not work properly on your Rails application due to the asset pipeline. They use FileAPI, so you could just include it manually for old browsers, or when you want to use FileAPI's toolkit anyway.

assignable_values now supports Rails 4.1 and Ruby 2.1.0.

The Rails community has been abuzz with object-oriented programming, SOLID principles, laws, design patterns, and other principles, practices, and patterns. We’ve (re)discovered new tools and techniques to separate and reuse logic, making code easier to test, understand, and maintain. Now that we’ve learned about all these new tools, when do we use them?

Presentation about optimizing Ruby on Rails apps.

From Nico Hagenburger (homify's lead frontend developer).

When ActiveRecord child objects are autosaved in Rails.

Databound provides Javascript a simple API to the Ruby on Rails CRUD.

Tries to expose a full model CRUD as an API. Not sure if this is useful for more refined requirements.

Now supports Rails 4.1 and Ruby 2.1.

Rails 4.0 introduced a helpful new method for ActiveRecord queries: where.not. It can make clunky queries easier to read.