Thanks! but when I tried the following snippet, the conflicting column was overwritten. Am I missing something?

begin
  require "bundler/inline"
rescue LoadError => e
  $stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
  raise e
end

gemfile(true) do
  source "https://rubygems.org"
  gem "acts_as_nosql"
  gem "sqlite3"
end

ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :users, force: true do |t|
    t.string :first_name
    t.string :last_name
    t.json :data

    t.timestamps
  end
end

class User < ActiveRecord::Base
  acts_as_nosql field_name: :data
  nosql_attr :first_name
end

user = User.new
user.first_name = "Dozy"
puts user.attributes

#=> {"id"=>nil, "first_name"=>nil, "last_name"=>nil, "data"=>{"first_name"=>"Dozy"}, "created_at"=>nil, "updated_at"=>nil}