title: Duplicate Logger output in Rails console
body: <p>I'm using pry-rails on one of my Rails projects but the console output is being duplicated everytime I use the Rails logger.</p>
  
  <p>Example:</p>
  
  <pre><code>Running via Spring preloader in process 21550
  Loading development environment (Rails 4.2.6)
  [1] pry(main)&gt; Rails.logger.info "Hello! Is there echo in here?"
  Hello! Is there echo in here?
  I, [2016-07-03T17:21:02.430621 #21550]  INFO -- : Hello! Is there echo in here?
  =&gt; true
  </code></pre>
  
  <p>So, I am getting a puts-like output and the the formal output.</p>
  
  <p>I'm sending my Gemfile, but as a summary:</p>
  
  <ul>
  <li>I'm using rails_12factor but its on production only and I checked and I am in the development environment.</li>
  <li>I've tried almost every configuration found elsewhere</li>
  <li>This is the only project that is showing this kind of trouble, but I can't find the great difference with the rest of them.</li>
  </ul>
  
  <p>Gemfile</p>
  
  <pre><code>source 'https://rubygems.org'
  ruby '2.2.3'
  
  gem 'bundler', '&gt;= 1.12'
  gem 'rails', '~&gt; 4.2.6'
  gem 'sass-rails', '~&gt; 5.0.0'
  gem 'uglifier', '&gt;= 1.3.0'
  gem 'coffee-rails', '~&gt; 4.0.0'
  gem 'jbuilder', '~&gt; 2.0'
  gem 'active_model_serializers'
  gem 'kaminari'
  gem 'sdoc', '~&gt; 0.4.0', group: :doc
  gem 'pg'
  gem 'pg_search'
  gem 'activerecord-postgis-adapter'
  gem 'eu_central_bank'
  gem 'money-rails'
  gem 'rack-cors', :require =&gt; 'rack/cors'
  gem 'puma'
  gem "refile", require: "refile/rails"
  gem "refile-mini_magick"
  gem "refile-s3"
  gem "rest-client"
  gem 'redis'
  gem 'sidekiq'
  gem 'sinatra'
  gem 'devise'
  gem 'will_paginate'
  gem 'postmark-rails'
  gem 'memcachier'
  gem 'dalli'
  gem 'newrelic_rpm'
  gem 'aasm'
  gem 'pry-rails' #, groups: [:test, :development]
  group :production do
    gem 'rails_12factor'
  end
  group :development do
    gem 'quiet_assets'
    gem 'spring'
    gem 'dotenv-rails'
    gem "better_errors"
    gem "binding_of_caller"
  end
  group :test, :development do
    gem 'awesome_print'
    gem 'faker'
    gem 'factory_girl_rails'
    gem "capybara"
    gem "selenium-webdriver"
  end
  gem 'angular-rails-templates'
  gem 'jader'
  </code></pre>