README.md in lockbox-0.3.7 vs README.md in lockbox-0.4.0

@@ -203,10 +203,12 @@
 User.create!(email: "[e-mail]")
 ```
 
 If you need to query encrypted fields, check out [Blind Index](https://github.com/ankane/blind_index).
 
+You can [migrate existing data](#migrating-existing-data) similarly to Active Record.
+
 ## Active Storage
 
 Add to your model:
 
 ```ruby
@@ -376,11 +378,11 @@
 
 ## Key Rotation
 
 To make key rotation easy, you can pass previous versions of keys that can decrypt.
 
-### Active Record
+### Active Record & Mongoid
 
 Update your model:
 
 ```ruby
 class User < ApplicationRecord
@@ -396,30 +398,10 @@
 Lockbox.rotate(User, attributes: [:email])
 ```
 
 Once all records are rotated, you can remove `previous_versions` from the model.
 
-### Mongoid
-
-Update your model:
-
-```ruby
-class User
-  encrypts :email, previous_versions: [{key: previous_key}]
-end
-```
-
-Use `master_key` instead of `key` if passing the master key.
-
-To rotate existing records, use:
-
-```ruby
-Lockbox.rotate(User, attributes: [:email])
-```
-
-Once all records are rotated, you can remove `previous_versions` from the model.
-
 ### Active Storage
 
 Update your model:
 
 ```ruby
@@ -460,12 +442,12 @@
 end
 ```
 
 Once all files are rotated, you can remove `previous_versions` from the model.
 
-### Strings
+### Local Files & Strings
 
-For strings, use:
+For local files and strings, use:
 
 ```ruby
 Lockbox.new(key: key, previous_versions: [{key: previous_key}])
 ```