Include keystrokes in a screencast

If you want to find out whether a Class object is directly inheriting from another class, use superclass:

ActiveRecord::RecordNotFound.super_class == ActiveRecord::ActiveRecordError # => true

To check if an...

I had a huge MySQL dump that took forever (as in: days) to import, while I actually just wanted to have the full database structure with some data to use on my development machine.

After trying several suggestions on how to speed up slow MySQL du...

Lets say we have a user with a contract whereas contract is a mounted carrierwave file.

Now we want to send the link to the contract in a mail. For this use case join the root_url with...

Association named 'variations' was not found; perhaps you misspelled it?

I just was hunting down a strange error with this model:

class Model
  placeholder = 'variations'
  
  has_many placeholder
  
  nested_scope :v...

Normally you can list all gems of the current ruby version with gem list, which also includes the gems of you Gemfile. These can be uninstalled with gem uninstall gemname.

List and uninstall a gem installed via Bundler from Github

This d...

To test whether a hash includes an expected sub-hash:

expect(user.attributes).to match(hash_including('name' => 'Bruce Wayne'))
expect(User).to receive(:create!).with(hash_including('name' => 'Bruce Wayne'))

When you call a method on an object, Ruby looks for the implementation of that method. It looks in the following places and uses the first implementation it finds:

1. Methods from the object's singleton class (an unnamed class that only exists fo...

If you defined your association via

class Article
  belongs_to "category"
end

and you try

Article.scoped(:include => :category)

you will get an error message

in `preload_one_association': Association named 'cat...

Sometimes you want to strip a text of every special char. If you use \W, the result might not be what you wanted:

    irb> "Eine längliche Kristall §$&&%& Lampe über dem Esstisch verschönert jedes noch so kahle   \n  Speisezimmer".gsub(/\W+/,...