У меня ошибка при использовании pow, но она отлично работает с rails s. Вот результаты того же кода на Heroku:www.contakapp.com

Я полагаю, что chunky_png-1.2.8 взят из базового камня или какой-то связанной проблемы Поэтому я также предоставляю весь свой гем-файл:

source 'https://rubygems.org'
ruby '1.9.3'

gem 'rails', '4.0.0'

#views
gem 'jquery-rails'            , '~> 2.2.1'
gem 'haml-rails'              , '~> 0.4'

#auth
gem 'omniauth-facebook'       , '~> 1.4.0'
gem 'omniauth-linkedin'       , '~> 0.1.0'

#API
gem 'twitter'                 , '~> 4.8.1'
gem 'rest-client'             , '~> 1.6.7'


# models
gem 'pg'

gem 'coffee-rails'
gem 'uglifier'
gem "font-awesome-rails"
gem 'sass-rails'
gem "compass-rails",    github: "milgner/compass-rails", ref: "1749c06f15dc4b058427e7969810457213647fb8"
gem "zurb-foundation", "~> 4.3.0"

group :development, :test do

end

group :development do

end

group :production, :staging do
    gem 'rails_12factor'
end

gemfile.lock

GIT
  remote: git://github.com/milgner/compass-rails.git
  revision: 1749c06f15dc4b058427e7969810457213647fb8
  ref: 1749c06f15dc4b058427e7969810457213647fb8
  specs:
    compass-rails (1.0.3)
      compass (>= 0.12.2, < 0.14)

GEM
  remote: https://rubygems.org/
  specs:
    actionmailer (4.0.0)
      actionpack (= 4.0.0)
      mail (~> 2.5.3)
    actionpack (4.0.0)
      activesupport (= 4.0.0)
      builder (~> 3.1.0)
      erubis (~> 2.7.0)
      rack (~> 1.5.2)
      rack-test (~> 0.6.2)
    activemodel (4.0.0)
      activesupport (= 4.0.0)
      builder (~> 3.1.0)
    activerecord (4.0.0)
      activemodel (= 4.0.0)
      activerecord-deprecated_finders (~> 1.0.2)
      activesupport (= 4.0.0)
      arel (~> 4.0.0)
    activerecord-deprecated_finders (1.0.3)
    activesupport (4.0.0)
      i18n (~> 0.6, >= 0.6.4)
      minitest (~> 4.2)
      multi_json (~> 1.3)
      thread_safe (~> 0.1)
      tzinfo (~> 0.3.37)
    arel (4.0.0)
    atomic (1.1.10)
    bcrypt-ruby (3.0.1)
    builder (3.1.4)
    chunky_png (1.2.8)
    coffee-rails (4.0.0)
      coffee-script (>= 2.2.0)
      railties (>= 4.0.0.beta, < 5.0)
    coffee-script (2.2.0)
      coffee-script-source
      execjs
    coffee-script-source (1.6.3)
    compass (0.12.2)
      chunky_png (~> 1.2)
      fssm (>= 0.2.7)
      sass (~> 3.1)
    erubis (2.7.0)
    execjs (1.4.0)
      multi_json (~> 1.0)
    faraday (0.8.7)
      multipart-post (~> 1.1)
    font-awesome-rails (3.0.2.0)
      railties (>= 3.1)
    fssm (0.2.10)
    haml (4.0.1)
      tilt
    haml-rails (0.4)
      actionpack (>= 3.1, < 4.1)
      activesupport (>= 3.1, < 4.1)
      haml (>= 3.1, < 4.1)
      railties (>= 3.1, < 4.1)
    hashie (1.2.0)
    hike (1.2.3)
    httpauth (0.2.0)
    i18n (0.6.4)
    jquery-rails (2.2.1)
      railties (>= 3.0, < 5.0)
      thor (>= 0.14, < 2.0)
    jwt (0.1.8)
      multi_json (>= 1.5)
    mail (2.5.4)
      mime-types (~> 1.16)
      treetop (~> 1.4.8)
    mime-types (1.23)
    minitest (4.7.5)
    multi_json (1.7.7)
    multipart-post (1.2.0)
    oauth (0.4.7)
    oauth2 (0.8.1)
      faraday (~> 0.8)
      httpauth (~> 0.1)
      jwt (~> 0.1.4)
      multi_json (~> 1.0)
      rack (~> 1.2)
    omniauth (1.1.3)
      hashie (~> 1.2)
      rack
    omniauth-facebook (1.4.0)
      omniauth-oauth2 (~> 1.0.2)
    omniauth-google (1.0.2)
      multi_json
      omniauth (~> 1.0)
      omniauth-oauth
    omniauth-linkedin (0.1.0)
      omniauth-oauth (~> 1.0)
    omniauth-oauth (1.0.1)
      oauth
      omniauth (~> 1.0)
    omniauth-oauth2 (1.0.3)
      oauth2 (~> 0.8.0)
      omniauth (~> 1.0)
    omniauth-twitter (1.0.0)
      multi_json (~> 1.3)
      omniauth-oauth (~> 1.0)
    pg (0.15.1)
    polyglot (0.3.3)
    rack (1.5.2)
    rack-test (0.6.2)
      rack (>= 1.0)
    rails (4.0.0)
      actionmailer (= 4.0.0)
      actionpack (= 4.0.0)
      activerecord (= 4.0.0)
      activesupport (= 4.0.0)
      bundler (>= 1.3.0, < 2.0)
      railties (= 4.0.0)
      sprockets-rails (~> 2.0.0)
    rails_12factor (0.0.2)
      rails_serve_static_assets
      rails_stdout_logging
    rails_serve_static_assets (0.0.1)
    rails_stdout_logging (0.0.1)
    railties (4.0.0)
      actionpack (= 4.0.0)
      activesupport (= 4.0.0)
      rake (>= 0.8.7)
      thor (>= 0.18.1, < 2.0)
    rake (10.1.0)
    rest-client (1.6.7)
      mime-types (>= 1.16)
    sass (3.2.9)
    sass-rails (4.0.0)
      railties (>= 4.0.0.beta, < 5.0)
      sass (>= 3.1.10)
      sprockets-rails (~> 2.0.0)
    simple_oauth (0.2.0)
    sorcery (0.8.2)
      bcrypt-ruby (~> 3.0.0)
      oauth (~> 0.4.4)
      oauth2 (~> 0.8.0)
    sprockets (2.10.0)
      hike (~> 1.2)
      multi_json (~> 1.0)
      rack (~> 1.0)
      tilt (~> 1.1, != 1.3.0)
    sprockets-rails (2.0.0)
      actionpack (>= 3.0)
      activesupport (>= 3.0)
      sprockets (~> 2.8)
    thor (0.18.1)
    thread_safe (0.1.0)
      atomic
    tilt (1.4.1)
    treetop (1.4.14)
      polyglot
      polyglot (>= 0.3.1)
    twitter (4.8.1)
      faraday (~> 0.8, < 0.10)
      multi_json (~> 1.0)
      simple_oauth (~> 0.2)
    tzinfo (0.3.37)
    uglifier (2.1.2)
      execjs (>= 0.3.0)
      multi_json (~> 1.0, >= 1.0.2)
    zurb-foundation (4.3.0)
      sass (>= 3.2.0)

PLATFORMS
  ruby

DEPENDENCIES
  coffee-rails
  compass-rails!
  font-awesome-rails
  haml-rails (~> 0.4)
  jquery-rails (~> 2.2.1)
  omniauth-facebook
  omniauth-google
  omniauth-linkedin
  omniauth-twitter
  pg
  rails (= 4.0.0)
  rails_12factor
  rest-client (~> 1.6.7)
  sass-rails
  sorcery
  twitter (~> 4.8.1)
  uglifier
  zurb-foundation (~> 4.3.0)