Asset precompile failure over environment mismatch

[ain]

Steps to reproduce:

1. Follow instruction to run FFCRM as Rails engine
2. Set up Docker environment based off ruby:2.5.3 with Puma and MariaDB
3. Import old database
4. Run stack with docker-compose up
5. Access http://localhost
6. Log in

What happens: instance spins up nicely

web_1  | Puma starting in single mode...
web_1  | * Version 3.12.0 (ruby 2.5.3-p105), codename: Llamas in Pajamas
web_1  | * Min threads: 1, max threads: 1
web_1  | * Environment: development
web_1  | * Listening on tcp://0.0.0.0:3000

but logging in results in error:

Sprockets::Rails::Helper::AssetNotPrecompiled in Home#index
Showing /usr/local/bundle/gems/fat_free_crm-0.18.1/app/views/home/index.html.haml where line #36 raised:

Asset was not declared to be precompiled in production.
Add `Rails.application.config.assets.precompile += %w( loading.gif )` to `config/initializers/assets.rb` and restart your server

What should happen: since application runs in development, assets should not be expected to be precompiled. Environment is correct:

$ docker-compose exec web env
PATH=/usr/local/bundle/bin:/usr/local/bundle/gems/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
HOSTNAME=29d1f78696cd
TERM=xterm
RAILS_ENV=development
RACK_ENV=development
RUBY_MAJOR=2.5
RUBY_VERSION=2.5.3
RUBY_DOWNLOAD_SHA256=1cc9d0359a8ea35fc6111ec830d12e60168f3b9b305a3c2578357d360fcf306f
RUBYGEMS_VERSION=2.7.8
BUNDLER_VERSION=1.17.1
GEM_HOME=/usr/local/bundle
BUNDLE_PATH=/usr/local/bundle
BUNDLE_SILENCE_ROOT_WARNING=1
BUNDLE_APP_CONFIG=/usr/local/bundle
HOME=/root

[ain]

The above happened on 0.18.1 (gem 'fat_free_crm', '~> 0.18.1')

Switching to master (gem 'fat_free_crm', :github => 'fatfreecrm/fat_free_crm') resolved the precompilation error.

[ain]

False alert. After running bundle exec rake db:migrate which also migrated to a Devise-based auth, login still ends up in a page with precompilation error (above).