diff --git a/CHANGELOG.md b/CHANGELOG.md
index 24c9db4..719e6a6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,8 @@
 
 - Add `if` option to inclusion constraints.
 - Add `name` option to constraints.
+- Add null constraint.
+- Ensure presence constraint enforces not null.
 
 ## 2.0.0
 
diff --git a/gemfiles/activerecord_4.gemfile.lock b/gemfiles/activerecord_4.gemfile.lock
index 80b6dfe..ae397bc 100644
--- a/gemfiles/activerecord_4.gemfile.lock
+++ b/gemfiles/activerecord_4.gemfile.lock
@@ -1,7 +1,7 @@
 PATH
   remote: ..
   specs:
-    rein (2.0.0)
+    rein (2.1.0)
       activerecord (>= 4.0.0, < 6)
       activesupport (>= 4.0.0, < 6)
 
@@ -69,7 +69,7 @@ DEPENDENCIES
   activerecord (~> 4.2.8)
   appraisal (~> 2.1)
   bundler (~> 1.14)
-  pg
+  pg (~> 0.20)
   rake (~> 12.0)
   rein!
   rspec (~> 3.5)
diff --git a/gemfiles/activerecord_5.gemfile.lock b/gemfiles/activerecord_5.gemfile.lock
index ea749ea..046505a 100644
--- a/gemfiles/activerecord_5.gemfile.lock
+++ b/gemfiles/activerecord_5.gemfile.lock
@@ -1,7 +1,7 @@
 PATH
   remote: ..
   specs:
-    rein (2.0.0)
+    rein (2.1.0)
       activerecord (>= 4.0.0, < 6)
       activesupport (>= 4.0.0, < 6)
 
@@ -68,7 +68,7 @@ DEPENDENCIES
   activerecord (~> 5.0.2)
   appraisal (~> 2.1)
   bundler (~> 1.14)
-  pg
+  pg (~> 0.20)
   rake (~> 12.0)
   rein!
   rspec (~> 3.5)
diff --git a/lib/rein/version.rb b/lib/rein/version.rb
index cd70746..d799ebb 100644
--- a/lib/rein/version.rb
+++ b/lib/rein/version.rb
@@ -1,3 +1,3 @@
 module Rein
-  VERSION = "2.0.0".freeze
+  VERSION = "2.1.0".freeze
 end