Asset not loading on production mode - ruby-on-rails

Question

Hello stackoverflow community,
I am building a Rails application which uses devise for authentication and it works fine on development mode. And when I host the app on Heroku everything works fine but the Checkbox next the question to save the password is missing.
I am using the Metronic Admin Theme which is based on Twitter Bootstrap.
Here is the checkbox which doesn't show up on production mode.
.form-actions
.checkbox
= f.check_box :remember_me
= f.label :remember_me, 'Passwort merken'
This is my production.rb file
Rails.application.configure do
# Settings specified here will take precedence over those in config/application.rb.
# Code is not reloaded between requests.
config.cache_classes = true
# 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
# Disable Rails's static asset server (Apache or nginx will already do this)
# --> nope, enabled it because we dont have no nginx!
config.serve_static_assets = true
# Compress JavaScripts and CSS
config.assets.compress = true
config.assets.js_compressor = :uglifier
config.assets.css_compressor = :sass
# Don't fallback to assets pipeline if a precompiled asset is missed
config.assets.compile = false
# change this if you want to expire all your assets
config.assets.version = '1.0'
# Generate digests for assets URLs
config.assets.digest = true
# 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
# Force all access to the app over SSL, use Strict-Transport-Security, and use secure cookies.
config.force_ssl = ENV['HTTPS'].to_bool
# Set to :debug to see everything in the log.
config.log_level = :info
# Enable locale fallbacks for I18n (makes lookups for any locale fall back to
# the I18n.default_locale when a translation can not be found)
config.i18n.fallbacks = true
# Send deprecation notices to registered listeners.
config.active_support.deprecation = :notify
# Disable automatic flushing of the log to improve performance.
config.autoflush_log = false
# Use default logging formatter so that PID and timestamp are not suppressed.
config.log_formatter = ::Logger::Formatter.new
# Do not dump schema after migrations.
config.active_record.dump_schema_after_migration = false
#Set timezone
config.time_zone = 'Bern'
# google analytics
GA.tracker = ENV['GA_TRACKER']
# mailers
config.action_mailer.delivery_method = :smtp
config.action_mailer.raise_delivery_errors = false
config.action_mailer.perform_deliveries = true
config.action_mailer.smtp_settings = {
address: ENV['SMPT_HOST'],
port: ENV['SMPT_PORT'].to_i,
domain: ENV['SMPT_DOMAIN'],
user_name: ENV['SMPT_USER'],
password: ENV['SMPT_PASS'],
authentication: :plain,
enable_starttls_auto: true
}
# default host for mailer and controllers
default_url_options = {
host: ENV['HOST_FOR_LINKS'], protocol: config.force_ssl ? 'https://' : 'http://'
}
config.action_mailer.default_url_options = default_url_options
routes.default_url_options = default_url_options
end
and my development.rb file
Rails.application.configure do
# Settings specified here will take precedence over those in config/application.rb.
# In the development environment your application's code is reloaded on
# every request. This slows down response time but is perfect for development
# since you don't have to restart the web server when you make code changes.
config.cache_classes = false
# Do not eager load code on boot.
config.eager_load = false
# Show full error reports and disable caching.
config.consider_all_requests_local = true
config.action_controller.perform_caching = false
# Don't care if the mailer can't send.
config.action_mailer.raise_delivery_errors = false
# Print deprecation notices to the Rails logger.
config.active_support.deprecation = :log
# Raise an error on page load if there are pending migrations.
config.active_record.migration_error = :page_load
# Debug mode disables concatenation and preprocessing of assets.
# This option may cause significant delays in view rendering with a large
# number of complex assets.
config.assets.debug = true
# Adds additional error checking when serving assets at runtime.
# Checks for improperly declared sprockets dependencies.
# Raises helpful error messages.
config.assets.raise_runtime_errors = true
# Raises error for missing translations
config.action_view.raise_on_missing_translations = true
# strong_parameters: raise exception
config.action_controller.action_on_unpermitted_parameters = :raise
# Force all access to the app over SSL, use Strict-Transport-Security, and use secure cookies.
config.force_ssl = ENV['HTTPS'].to_bool
# mailcatcher
config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = { address: "localhost", port: 1025 }
#Set timezone
config.time_zone = 'Bern'
# default host for mailer and controllers
default_url_options = {
host: ENV['HOST_FOR_LINKS'], protocol: config.force_ssl ? 'https://' : 'http://'
}
config.action_mailer.default_url_options = default_url_options
routes.default_url_options = default_url_options
# Live reload for debugging
if ENV['LIVE_RELOAD'].to_bool
config.middleware.use Rack::LiveReload
end
end