diff --git a/README.markdown b/README.markdown
index 0621e15..e6d8a3d 100644
--- a/README.markdown
+++ b/README.markdown
@@ -73,10 +73,6 @@ Some people report much faster speeds with `:deletion` while others say `:trunca
 
 If you are using ActiveRecord then take a look at the [additional options](#additional-activerecord-options-for-truncation) available for `:truncation`.
 
-## Dependencies
-
-Because database_cleaner supports multiple ORMs, it doesn't make sense to include all the dependencies for each one in the gemspec. However, the DataMapper adapter does depend on dm-transactions. Therefore, if you use DataMapper, you must include dm-transactions in your Gemfile/bundle/gemset manually.
-
 ## How to use
 
 ```ruby
diff --git a/adapters/database_cleaner-data_mapper/Gemfile.lock b/adapters/database_cleaner-data_mapper/Gemfile.lock
index 76c25d5..72ced3b 100644
--- a/adapters/database_cleaner-data_mapper/Gemfile.lock
+++ b/adapters/database_cleaner-data_mapper/Gemfile.lock
@@ -9,12 +9,13 @@ PATH
     database_cleaner-data_mapper (1.8.0)
       database_cleaner (~> 1.8.0)
       datamapper
+      dm-transactions
 
 GEM
   remote: https://rubygems.org/
   specs:
     addressable (2.3.6)
-    bcrypt (3.1.7)
+    bcrypt (3.1.12)
     bcrypt-ruby (3.1.5)
       bcrypt (>= 3.1.3)
     data_objects (0.10.14)
@@ -68,8 +69,8 @@ GEM
       data_objects (= 0.10.14)
     fastercsv (1.5.5)
     json (1.8.6)
-    json_pure (1.8.1)
-    multi_json (1.2.0)
+    json_pure (1.8.6)
+    multi_json (1.13.1)
     rake (10.4.2)
     rspec (3.7.0)
       rspec-core (~> 3.7.0)
diff --git a/adapters/database_cleaner-data_mapper/database_cleaner-data_mapper.gemspec b/adapters/database_cleaner-data_mapper/database_cleaner-data_mapper.gemspec
index 55dceac..39e24d2 100644
--- a/adapters/database_cleaner-data_mapper/database_cleaner-data_mapper.gemspec
+++ b/adapters/database_cleaner-data_mapper/database_cleaner-data_mapper.gemspec
@@ -23,6 +23,7 @@ Gem::Specification.new do |spec|
 
   spec.add_dependency "database_cleaner", "~> 1.8.0"
   spec.add_dependency "datamapper"
+  spec.add_dependency "dm-transactions"
 
   spec.add_development_dependency "rake", "~> 10.0"
   spec.add_development_dependency "bundler", "~> 1.16"