Could not load 'active_record/connection_adapters/oracle_enhanced_adapter'.
   Make sure that the adapter in config/database.yml is valid.
   If you use an adapter other than 'mysql', 'mysql2', 'postgresql'
   or 'sqlite3' add the necessary adapter gem to the Gemfile. (LoadError)

ruby 1.9.3 installed on /usr/local/bin
  required gems installed on /usr/local/lib/ruby/gems/1.9.3/gems
     * activemodel (4.2.4)
     * activerecord (4.2.4)
     * activerecord-oracle_enhanced-adapter (1.6.7)
     * activesupport (4.2.4)

  oracle instant client installed on /usr/local/share/instantclient_12_1
  Path is set: export LD_LIBRARY_PATH=/usr/local/share/instantclient_12_1

source 'https://rubygems.org'

   gem 'cucumber', '2.1.0'
   gem 'activerecord', '4.2.4'
   gem 'page-object', '1.2.0'
   gem 'activerecord-oracle_enhanced-adapter', '1.6.7'
   gem 'rspec'
   gem 'ruby-oci8', '2.2.2'
   gem 'nw_credentials', '2.0.3'

DEV_DB:
      adapter: oracle_enhanced
      database: (DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=xxxx.xxx.net)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=xxxx.xxx.net)))

Cucumber 2.1.0
   Selenium Webdriver: 2.53.4
   Linux: x86_64 x86_64 x86_64 GNU/Linux