[Ruby on Rails CLI] commands

1. $ rails API

$ rails new api-project --api --no-sprockets -d postgresql                     
                           |       |                    |
                           |       v                    |
                           v      NO Asset Pipeline     |
                         only API                       v
                                                      use Postgresql as DB
$ rails generate model contact
$ rails g controller v1/contacts

2. $ rails create project(p), start p, get route's of p

$ rails new test-app
$ rails server
 or
$ rails s

$ rake routes
$ rake routes | grep article

3. $ rails errors in db

article.errors.any?
article.errors.full_message

4. $ rails generate new migration and schema

// Scaffold generator command to create Article model,
// articles controller, views for articles and migration file to create articles 

$ rails generate scaffold Article title:string description:text

$ rails generate migration create_article
Then
$ rails db:migrate
$ rails db:rollback !!! NOT BEST WAY

IF YOU MADE A MISTAKE - create new migration file like this
$ rails generate migration add_description_to_articles


// IN RAILS 4
$ rake db:migrate

// IN RAILS 5
$ rails db:migrate

5. $ rails insert object to database

// DATABASE
$ rails console
Article.all
Article
article = Article.new
article.title = "Some text"
article.save -> After this it will be saved to database
***
begin transaction
  Article Create (0.8ms)  INSERT INTO "articles" ("title", "created_at", "updated_at") 
VALUES (?, ?, ?)  [["title", "Some title"], ["created_at", "2019-08-30 14:46:34.678509"], ["updated_at", "2019-08-30 14:46:34.678509"]]
   (7.7ms)  commit transaction
   ***
   
// SAME IN TWO LINES
article = Article.new(title: "Some title")
article.save

// SAME IN ONE LINES
Article.create(title: "Some title")

$ exit

6. $ rails update ant delete by console

	// UPDATE
$ rails console
Article.all
Article.find(1) // ID
article
article.title = "Another text"
article.save -> After this it will be saved to database

// Delete
Article.find(1) // ID
article
article.destroy

$ exit

7. FORM HELPERS DOCS

# Example
<%= form_with do %>
  Form contents
<% end %>