$ luarocks install lapis-annotate

$ lapis annotate help
Usage: lapis annotate [-h] [--preload-module <name>]
       [--format {sql,table,generate_enum_comments}] [--print]
       <files> [<files>] ...

Extract schema information from model's table to comment model

Arguments:
   files                 Paths to model classes to annotate (eg. models/first.moon models/second.moon ...)

Options:
   -h, --help            Show this help message and exit.
   --preload-module <name>
                         Module to require before annotating a model
   --format {sql,table,generate_enum_comments}
                         What dump format to use (default: sql)
   --print, -p           Print the output instead of editing the model files

$ lapis annotate models/my_model.moon

import Model from require "lapis.db.model"

class UserIpAddresses extends Model
  @timestamp: true
  @primary_key: {"user_id", "ip"}

import Model from require "lapis.db.model"

-- Generated schema dump: (do not edit)
--
-- CREATE TABLE user_ip_addresses (
--   user_id integer NOT NULL,
--   ip character varying(255) NOT NULL,
--   created_at timestamp without time zone NOT NULL,
--   updated_at timestamp without time zone NOT NULL
-- );
-- ALTER TABLE ONLY user_ip_addresses
--   ADD CONSTRAINT user_ip_addresses_pkey PRIMARY KEY (user_id, ip);
-- CREATE INDEX user_ip_addresses_ip_idx ON user_ip_addresses USING btree (ip);
--
class UserIpAddresses extends Model
  @timestamp: true
  @primary_key: {"user_id", "ip"}