Rakefile

require "active_record"
require "yaml"

namespace :db do

  db_config       = YAML.safe_load(File.open("config/database.yml"))
  db_config_admin = db_config.merge("database" => "postgres", "schema_search_path" => "public")

  desc "Create the database"
  task :create do
    ActiveRecord::Base.establish_connection(db_config_admin)
    ActiveRecord::Base.connection.create_database(db_config["database"])
    puts "Database created."
  end

  desc "Migrate the database"
  task :migrate do
    ActiveRecord::Base.establish_connection(db_config)
    ActiveRecord::MigrationContext.new("db/migrate/").migrate
    Rake::Task["db:schema"].invoke
    puts "Database migrated."
  end

  desc "Drop the database"
  task :drop do
    ActiveRecord::Base.establish_connection(db_config_admin)
    ActiveRecord::Base.connection.drop_database(db_config["database"])
    puts "Database deleted."
  end

  desc "Reset the database"
  task reset: [:drop, :create, :migrate]

  desc "Create a db/schema.rb file that is portable against any DB supported by AR"
  task :schema do
    ActiveRecord::Base.establish_connection(db_config)
    require "active_record/schema_dumper"
    filename = "db/schema.rb"
    File.open(filename, "w:utf-8") do |file|
      ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.connection, file)
    end
  end

end

namespace :g do
  desc "Generate migration"
  task :migration do
    name = ARGV[1] || raise("Specify name: rake g:migration your_migration")
    timestamp = Time.now.strftime("%Y%m%d%H%M%S")
    path = File.expand_path("../db/migrate/#{timestamp}_#{name}.rb", __FILE__)
    migration_class = name.split("_").map(&:capitalize).join

    `touch #{path}`
    File.open(path, "w") do |file|
      file.write <<~MIGRATION
        class #{migration_class} < ActiveRecord::Migration[5.2]
          def self.up
          end
          def self.down
          end
        end
      MIGRATION
    end

    puts "Migration #{path} created"
    abort # needed stop other tasks
  end
end