README.md in lockbox-0.5.0 vs README.md in lockbox-0.6.0

@@ -195,10 +195,38 @@
 class User < ApplicationRecord
   blind_index :email, migrating: true
 end
 ```
 
+#### Model Changes
+
+If tracking changes to model attributes, be sure to remove or redact encrypted attributes.
+
+PaperTrail
+
+```ruby
+class User < ApplicationRecord
+  # for an encrypted history (still tracks ciphertext changes)
+  has_paper_trail skip: [:email]
+
+  # for no history (add blind indexes as well)
+  has_paper_trail skip: [:email, :email_ciphertext]
+end
+```
+
+Audited
+
+```ruby
+class User < ApplicationRecord
+  # for an encrypted history (still tracks ciphertext changes)
+  audited except: [:email]
+
+  # for no history (add blind indexes as well)
+  audited except: [:email, :email_ciphertext]
+end
+```
+
 #### Decryption
 
 To decrypt data outside the model, use:
 
 ```ruby
@@ -729,17 +757,17 @@
 
 For Ubuntu 20.04 and 18.04, use:
 
 ```yml
     - name: Install Libsodium
-      run: sudo apt-get install libsodium23
+      run: sudo apt-get update && sudo apt-get install libsodium23
 ```
 
 For Ubuntu 16.04, use:
 
 ```yml
     - name: Install Libsodium
-      run: sudo apt-get install libsodium18
+      run: sudo apt-get update && sudo apt-get install libsodium18
 ```
 
 ##### Travis CI
 
 On Bionic, add to `.travis.yml`: