RAILS_VERSIONS = { '4.0.13' => { 'mysql2' => '~> 0.3.18', 'activerecord-oracle_enhanced-adapter' => '~> 1.5.0' }, '4.1.15' => { 'mysql2' => '~> 0.3.18', 'activerecord-oracle_enhanced-adapter' => '~> 1.5.0' }, '4.2.8' => { 'activerecord-oracle_enhanced-adapter' => '~> 1.6.0' }, '5.0.3' => { 'activerecord-oracle_enhanced-adapter' => '~> 1.7.0', 'ruby-oci8' => '' }, '5.1.1' => { 'activerecord-oracle_enhanced-adapter' => '~> 1.8.0', 'ruby-oci8' => '' } } RAILS_VERSIONS.each do |version, gems| appraise "rails_#{version}" do gem 'rails', version gems.each do |name, version| if version.empty? gem name else gem name, version end end end end