To support ActiveRecord unit tests for IBM DB2

Gemfile

@@ -99,3 +99,6 @@ if ENV['ORACLE_ENHANCED_PATH'] || ENV['ORACLE_ENHANCED']
     gem "activerecord-oracle_enhanced-adapter", :git => "git://github.com/rsim/oracle-enhanced.git"
   end
 end
+
+# A gem necessary for ActiveRecord tests with Oracle database
+gem "ibm_db" if ENV['IBM_DB']

activerecord/test/config.example.yml

@@ -37,11 +37,13 @@ connections:
 
   db2:
     arunit:
+      adapter:  ibm_db
       host:     localhost
       username: arunit
       password: arunit
       database: arunit
     arunit2:
+      adapter:  ibm_db
       host:     localhost
       username: arunit
       password: arunit