rails6 upsert example

Gemfile

source "https://rubygems.org"

git_source(:github) { |repo| "https://github.com/#{repo}.git" }

gem "rails", github: 'rails/rails', ref: '1816c4f'
gem "pg"

setup.rb

require "bundler/setup"
require "active_record"
require "logger"

ActiveRecord::Base.establish_connection(adapter: "postgresql", host: "localhost", database: "postgres", username: "postgres", password: "password")
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :posts, force: true do |t|
    t.string :slug, null: false
    t.text :post
    t.timestamps
  end

  add_index :posts, :slug, unique: true
end

class Post < ActiveRecord::Base
  validates :slug, uniqueness: true, presence: true
end