Steps to Deploy ROR on render

production.rb

require "active_support/core_ext/integer/time"

Rails.application.configure do
  # Settings specified here will take precedence over those in config/application.rb.

  # Code is not reloaded between requests.
  config.enable_reloading = false

  # Eager load code on boot. This eager loads most of Rails and
  # your application in memory, allowing both threaded web servers
  # and those relying on copy on write to perform better.
  # Rake tasks automatically ignore this option for performance.
  config.eager_load = true

  # Full error reports are disabled and caching is turned on.
  config.consider_all_requests_local       = false
  config.action_controller.perform_caching = true

  # Ensures that a master key has been made available in ENV["RAILS_MASTER_KEY"], config/master.key, or an environment
  # key such as config/credentials/production.key. This key is used to decrypt credentials (and other encrypted files).
  # config.require_master_key = true

  # Disable serving static files from the `/public` folder by default since
# Apache or NGINX already handles this.
config.public_file_server.enabled = ENV['RAILS_SERVE_STATIC_FILES'].present? || ENV['RENDER'].present?

  # Enable static file serving from the `/public` folder (turn off if using NGINX/Apache for it).
  config.public_file_server.enabled = true

  # Compress CSS using a preprocessor.
  # config.assets.css_compressor = :sass

  # Do not fallback to assets pipeline if a precompiled asset is missed.
  config.assets.compile = false

  # Enable serving of images, stylesheets, and JavaScripts from an asset server.
  # config.asset_host = "http://assets.example.com"

  # Specifies the header that your server uses for sending files.
  # config.action_dispatch.x_sendfile_header = "X-Sendfile" # for Apache
  # config.action_dispatch.x_sendfile_header = "X-Accel-Redirect" # for NGINX

  # Store uploaded files on the local file system (see config/storage.yml for options).
  config.active_storage.service = :local

  # Mount Action Cable outside main process or domain.
  # config.action_cable.mount_path = nil
  # config.action_cable.url = "wss://example.com/cable"
  # config.action_cable.allowed_request_origins = [ "http://example.com", /http:\/\/example.*/ ]

  # Assume all access to the app is happening through a SSL-terminating reverse proxy.
  # Can be used together with config.force_ssl for Strict-Transport-Security and secure cookies.
  # config.assume_ssl = true

  # Force all access to the app over SSL, use Strict-Transport-Security, and use secure cookies.
  config.force_ssl = true

  # Log to STDOUT by default
  config.logger = ActiveSupport::Logger.new(STDOUT)
    .tap  { |logger| logger.formatter = ::Logger::Formatter.new }
    .then { |logger| ActiveSupport::TaggedLogging.new(logger) }

  # Prepend all log lines with the following tags.
  config.log_tags = [ :request_id ]

  # Info include generic and useful information about system operation, but avoids logging too much
  # information to avoid inadvertent exposure of personally identifiable information (PII). If you
  # want to log everything, set the level to "debug".
  config.log_level = ENV.fetch("RAILS_LOG_LEVEL", "info")

  # Use a different cache store in production.
  # config.cache_store = :mem_cache_store

  # Use a real queuing backend for Active Job (and separate queues per environment).
  # config.active_job.queue_adapter     = :resque
  # config.active_job.queue_name_prefix = "cash_in_out_production"

  config.action_mailer.perform_caching = false

  # Ignore bad email addresses and do not raise email delivery errors.
  # Set this to true and configure the email server for immediate delivery to raise delivery errors.
  # config.action_mailer.raise_delivery_errors = false

  # Enable locale fallbacks for I18n (makes lookups for any locale fall back to
  # the I18n.default_locale when a translation cannot be found).
  config.i18n.fallbacks = true

  # Don't log any deprecations.
  config.active_support.report_deprecations = false

  # Do not dump schema after migrations.
  config.active_record.dump_schema_after_migration = false

  # Enable DNS rebinding protection and other `Host` header attacks.
  # config.hosts = [
  #   "example.com",     # Allow requests from example.com
  #   /.*\.example\.com/ # Allow requests from subdomains like `www.example.com`
  # ]
  # Skip DNS rebinding protection for the default health check endpoint.
  # config.host_authorization = { exclude: ->(request) { request.path == "/up" } }
end

puma.rb

# Puma can serve each request in a thread from an internal thread pool.
# The `threads` method setting takes two numbers: a minimum and maximum.
# Any libraries that use thread pools should be configured to match
# the maximum value specified for Puma. Default is set to 5 threads for minimum
# and maximum; this matches the default thread size of Active Record.
#
max_threads_count = ENV.fetch("RAILS_MAX_THREADS") { 5 }
min_threads_count = ENV.fetch("RAILS_MIN_THREADS") { max_threads_count }
threads min_threads_count, max_threads_count

# Specifies the `port` that Puma will listen on to receive requests; default is 3000.
#
port        ENV.fetch("PORT") { 3000 }

# Specifies the `environment` that Puma will run in.
#
environment ENV.fetch("RAILS_ENV") { "development" }

# Specifies the `pidfile` that Puma will use.
pidfile ENV.fetch("PIDFILE") { "tmp/pids/server.pid" }

# Specifies the number of `workers` to boot in clustered mode.
# Workers are forked web server processes. If using threads and workers together
# the concurrency of the application would be max `threads` * `workers`.
# Workers do not work on JRuby or Windows (both of which do not support
# processes).
#
workers ENV.fetch("WEB_CONCURRENCY") { 4 }
# Use the `preload_app!` method when specifying a `workers` number.
# This directive tells Puma to first boot the application and load code
# before forking the application. This takes advantage of Copy On Write
# process behavior so workers use less memory.
#
preload_app!
# Allow puma to be restarted by `rails restart` command.
plugin :tmp_restart

render-build.sh

#!/usr/bin/env bash
# exit on error
set -o errexit

bundle install
bundle exec rails assets:precompile
bundle exec rails assets:clean
bundle exec rails db:migrate

ensure the above is added in bin/render-build.sh

hen run command:
chmod a+x bin/render-build.sh