Add nullable foreign key in Rails

Add nullable foreign key in Rails

ruby-on-rails ruby ruby-on-rails-4 rails-activerecord ruby-on-rails-4.2

ruby

can't connect localhost:3000 ruby on rails in vagrant

ruby-on-rails ruby ruby-on-rails-4 vagrant ruby-on-rails-4.2

ruby

El Capitan upgrade: Library not loaded: /usr/local/lib/libmysqlclient.18.dylib

mysql ruby macos osx-elcapitan ruby-on-rails-4.2

ruby

undefined method `cache' for nil:NilClass after upgrading to rails 4.2.5.1

ruby-on-rails ruby ruby-on-rails-4.2

ruby

RangeError for simple integer assignment in Rails 4.2.0 that should be caught by validation

ruby-on-rails ruby postgresql activerecord ruby-on-rails-4.2

ruby

What is the best way to use HTTP 2 with AWS Elastic beanstalk

ruby-on-rails ruby amazon-elastic-beanstalk http2 ruby-on-rails-4.2

ruby