allow bypassing transaction wrapper

README.md

@@ -60,6 +60,7 @@ Use an initializer file for configuration.
 
 - `migration_table_name (default = 'rake_task_migrations')`
 - `migration_namespace (default = :migrations)`
+- `wrap_migrations_in_transaction (default = true)`
 
 #### Example:
 
@@ -69,6 +70,7 @@ Use an initializer file for configuration.
 Rake::TaskMigration.config do |config|
   config.migration_table_name = 'table_name'
   config.migration_namespace  = 'namespace'
+  config.wrap_migrations_in_transaction = false
 end
 ```
 

lib/rake/task_migration.rb

@@ -16,6 +16,9 @@ module TaskMigration
     mattr_accessor :migration_namespace
     self.migration_namespace  = DEFAULT_NAMESPACE
 
+    mattr_accessor :wrap_migrations_in_transaction
+    self.wrap_migrations_in_transaction = true
+
     class << self
       def config
         yield self

lib/rake/task_migration/migrator.rb

@@ -28,7 +28,7 @@ def migrate_task(task)
 
         announce "#{task}: migrating"
 
-        ActiveRecord::Base.transaction do
+        with_optional_transaction_wrapper do
           time = Benchmark.measure do
             invoke(task)
           end
@@ -44,6 +44,14 @@ def migrate_task(task)
         end
       end
 
+      def with_optional_transaction_wrapper
+        if Rake::TaskMigration.wrap_migrations_in_transaction
+          ActiveRecord::Base.transaction { yield }
+        else
+          yield
+        end
+      end
+
       def invoke(task)
         Rake::Task[task].invoke
       end