Ruby on Rails

Getting this error re rack I think the problem is an unwanted gem or gem version somewhere Sometimes you shouldn't put gems in the Gemfile even if you're using them, it borks everything so I'm thinking there's a gem implicitly stated in my Gemfile that shouldn't be there

Bundler could not find compatible versions for gem "rack":
  In Gemfile:
    rails (= 5.0.0.1) was resolved to 5.0.0.1, which depends on
      actionpack (= 5.0.0.1) was resolved to 5.0.0.1, which depends on
        rack (~> 2.0)

    capybara was resolved to 2.11.0, which depends on
      rack (>= 1.0.0)

    mobu was resolved to 0.0.2, which depends on
      rack (~> 1.4)

    omniauth-facebook was resolved to 4.0.0, which depends on
      omniauth-oauth2 (~> 1.2) was resolved to 1.4.0, which depends on
        oauth2 (~> 1.0) was resolved to 1.2.0, which depends on
          rack (< 3, >= 1.2)

    omniauth was resolved to 1.3.1, which depends on
      rack (< 3, >= 1.0)

    sidekiq was resolved to 4.2.7, which depends on
      rack-protection (>= 1.5.0) was resolved to 1.5.3, which depends on
        rack

    sass-rails was resolved to 5.0.6, which depends on
      sprockets (< 4.0, >= 2.8) was resolved to 3.7.0, which depends on
        rack (< 3, > 1)

    thin was resolved to 1.7.0, which depends on
      rack (< 3, >= 1)

    devise was resolved to 4.2.0, which depends on
      warden (~> 1.2.3) was resolved to 1.2.6, which depends on
        rack (>= 1.0)

    devise was resolved to 4.2.0, which depends on
      warden (~> 1.2.3) was resolved to 1.2.6, which depends on
        rack (>= 1.0)

Here's my Gemfile

source "https://rubygems.org"

# Bundle edge Rails instead: gem "rails", github: "rails/rails"
gem "rails", "5.0.0.1"
# Use sqlite3 as the database for Active Record
gem "sqlite3"
# Use mysql2 as the database for Active Record
gem "mysql2"
# Use SCSS for stylesheets
gem "sass-rails"
# Use Uglifier as compressor for JavaScript assets
gem "uglifier"
# Use CoffeeScript for .js.coffee assets and views
gem "coffee-rails"
# See https://github.com/sstephenson/execjs#readme for more supported runtimes
# gem "therubyracer",  platforms: :ruby

gem "lol_dba"
# Use jquery as the JavaScript library
gem "jquery-rails"
# Turbolinks makes following links in your web application faster. Read more: https://github.com/rails/turbolinks
gem "jquery-ui-rails"

gem "turbolinks"
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem "jbuilder"
# bundle exec rake doc:rails generates the API under doc/api.
gem "sdoc"

# Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
gem "spring",        group: :development

#random key generate
gem "webget_ruby_secure_random"

#pagination
gem "will_paginate"

gem 'kaminari'

# Haml
gem "haml"

# Haml scaffolding functions
gem "haml-rails"

# Process attachiment
gem "paperclip"

gem 'aws-sdk'

gem "devise"
gem "cancan"
gem "omniauth"
gem "omniauth-facebook"
gem "omniauth-twitter"
gem "omniauth-google_oauth2"
gem 'omniauth-linkedin'
gem 'omniauth-github'

#gem "acts-as-messageable"

gem 'simple-private-messages', '0.0.0', :git => 'git://github.com/jongilbraith/simple-private-messages.git'

gem "font-awesome-rails"
gem "famfamfam_flags_rails"

gem "activeadmin", github: "activeadmin"
#gem "activeadmin-dragonfly", github: "stefanoverna/activeadmin-dragonfly"
#gem "activeadmin-wysihtml5", github: "stefanoverna/activeadmin-wysihtml5"

gem 'rails_12factor'

gem "mail"

gem "country_select"

gem 'countries'

gem "domp"

gem "sidekiq"

gem 'valid_email', require: 'valid_email/validate_email'

gem "faye"
gem "thin"

# 'newrelic_rpm'
gem 'newrelic_rpm'

# no longer required as cloudfront now is doing all the work
# gem 'asset_sync'

# gem 'font_assets'

gem 'mobu'

gem "remotipart"

gem 'gabba'

#seedbank
gem "seedbank"

gem 'draper'

gem 'exception_notification'

gem 'mixpanel-ruby'

group :development, :test do
  gem 'rspec-rails'
  gem 'factory_girl_rails'
  gem 'capybara'
  gem 'database_cleaner'
  gem 'fabrication'
  gem 'ffaker'
  gem 'seed_dump'
  gem 'sweet-logger'  # added to Development env according to http://nikolay.rocks/2015-08-06-unslow-rails-dev
end

# gem to convert russian letters into latin letters, so called "translit"
gem 'cyrillizer'

# required to fix the issue with CORS and AWesome Font
# see http://blog.jdwyah.com/2014/09/cors-for-rails-heroku-cloudfront-for.html
gem 'rack-cors'

gem 'puma'

gem 'acts-as-taggable-on'

gem 'rails4-autocomplete'

gem 'ckeditor'

gem "lazyload-rails"

gem "figaro"


# Use ActiveModel has_secure_password
# gem "bcrypt"

# Use unicorn as the app server
# gem "unicorn"

# Use Capistrano for deployment
# gem "capistrano-rails"

# Use debugger
# gem "debugger", group: [:development, :test]


gem "letter_opener", :group => :development

gem 'acts_as_votable'

# ace javascript editor
# gem 'ace-rails-ap'

# shows maintenance page (public/maintenance.html if exists)
gem 'rack-maintenance'