diff --git a/CHANGELOG.md b/CHANGELOG.md
index 448bc12..228cac7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+## [2.6.0](https://github.com/tsuwatch/nazrin/compare/v2.5.0...v2.6.0)
+
+### Features:
+
+* Implement batch operation [#27](https://github.com/tsuwatch/nazrin/pull/27) - [@AMHOL](https://github.com/AMHOL)
+
 ## [2.5.0](https://github.com/tsuwatch/nazrin/compare/v2.4.0...v2.5.0)
 
 ### Features:
diff --git a/README.md b/README.md
index 996a3a7..b062160 100644
--- a/README.md
+++ b/README.md
@@ -68,6 +68,7 @@ class Post < ActiveRecord::Base
 end
 ```
 
+### `.search`
 ```ruby
 result = Post.search(where: :foo, includes: :bar).size(1).start(0).query("(and 'content')").query_parser('structured').execute
 => [#<Post id: 1, content: "content">]
@@ -76,6 +77,20 @@ result.facets
 => {}
 ```
 
+### `.batch_operation`
+```ruby
+post1 = Post.create
+post2 = Post.create
+post3 = Post.create
+post3.destroy
+
+Post.batch_operation(
+  add: [post1, post2],
+  delete: [post3]
+)
+```
+
+
 ### Supported pagination libraries
 If you want to use other supported pagination libraries, for example, `nazrin-kaminari` generates `Kaminari::PaginatableArray` instead of `Nazrin::PaginatedArray`.
 
diff --git a/lib/nazrin/version.rb b/lib/nazrin/version.rb
index 8cd488a..bd51082 100644
--- a/lib/nazrin/version.rb
+++ b/lib/nazrin/version.rb
@@ -1,3 +1,3 @@
 module Nazrin
-  VERSION = '2.5.0'
+  VERSION = '2.6.0'
 end