diff --git a/gemfiles/activerecord_4.2.gemfile b/gemfiles/activerecord_4.2.gemfile
index c34356de..8b9c2b75 100644
--- a/gemfiles/activerecord_4.2.gemfile
+++ b/gemfiles/activerecord_4.2.gemfile
@@ -7,7 +7,7 @@ gem "activerecord", "~> 4.2.0"
 platforms :ruby do
   gem "mysql2", "< 0.5"
   gem "pg", "~> 0.21"
-  gem "sqlite3", "~> 1.3.13"
+  gem "sqlite3", "~> 1.3", "< 1.4"
 end
 
 platforms :jruby do
diff --git a/gemfiles/activerecord_5.0.gemfile b/gemfiles/activerecord_5.0.gemfile
index da91aa40..83adaeb4 100644
--- a/gemfiles/activerecord_5.0.gemfile
+++ b/gemfiles/activerecord_5.0.gemfile
@@ -7,7 +7,7 @@ gem "activerecord", "~> 5.0.0"
 platforms :ruby do
   gem "mysql2"
   gem "pg"
-  gem "sqlite3", "~> 1.3.13"
+  gem "sqlite3", "~> 1.3", "< 1.4"
 end
 
 platforms :jruby do
diff --git a/lib/closure_tree.rb b/lib/closure_tree.rb
index fb03939c..bcb98261 100644
--- a/lib/closure_tree.rb
+++ b/lib/closure_tree.rb
@@ -1,4 +1,5 @@
 require 'active_record'
+require 'active_support/core_ext/string/strip'
 
 module ClosureTree
   extend ActiveSupport::Autoload