Some useful rails command

rails.sh

# adding a column to an existing table
rails g migration AddNameToUsers name:string
  # or
rails generate migration add_image_to_pictures image_id:string

# to remove
rails d migration AddNameToUsers name:string

# remove column from model
rails g migration RemoveProjectIDFromProjects project_id:string

# install rspec
bin/rails g rspec:install

# has_many association
rails g scaffold Comment post:references
# hash many association to more models
rails g scaffold Favorite post:references user:references
# generate the project first
rails g model Task description:string done:boolean project:belongs_to

# annotate ~> annotate

# install devise
rails g devise:install
rails g devise User

# generate model
rails g model Picture image:string

# see all the generate options
rails generate -h

# creating a scaffold controller for an existing model
rails g scaffold User name --skip
#or  rails g scaffold_controller User

# creating a scaffold model
rails generate scaffold Book title:string author:string

# restaurant and user has_and_belongs_to_many relationship.
rails g migration create_restaurants_users

#Using resource Instead of using the scaffold generator;
#resource generator will not generate all the files and methods created by the scaffold generator.
rails g resource Record title date:date amount:float

# drop and up a specific migration
rake db:migrate:redo VERSION=my_version
# or
rake db:migrate:down VERSION=20160111162227
rake db:migrate:up VERSION=20160111162227
# search by association
Account.joins(:trades).group('accounts.id').having('count(account_id) >2')

# rspec api mock
https://www.honeybadger.io/blog/ruby-external-api-test/

#__________________

# select box from a hash
<%= select_tag('lead[order_type]', options_from_collection_for_select(@states_list["dachdecker"]["order_type"], :first, :last), options = {prompt: "Bitte wählen"}) %>