README.md in strong_migrations-0.5.0 vs README.md in strong_migrations-0.5.1

@@ -32,11 +32,11 @@
 - [[+]](#adding-a-foreign-key) adding a foreign key
 - [[+]](#renaming-or-changing-the-type-of-a-column) changing the type of a column
 - [[+]](#renaming-or-changing-the-type-of-a-column) renaming a column
 - [[+]](#renaming-a-table) renaming a table
 - [[+]](#creating-a-table-with-the-force-option) creating a table with the `force` option
-- [[+]](#using-change_column_null) using `change_column_null`
+- [[+]](#setting-not-null-on-an-existing-column) setting `NOT NULL` on an existing column
 - [[+]](#adding-a-json-column) adding a `json` column
 
 Optional checks:
 
 - [[+]](#removing-an-index) removing an index non-concurrently
@@ -359,11 +359,11 @@
     end
   end
 end
 ```
 
-### Using change_column_null
+### Setting `NOT NULL` on an existing column
 
 #### Bad
 
 In Postgres, setting `NOT NULL` on an existing column requires an `AccessExclusiveLock`, which is expensive on large tables.
 
@@ -401,11 +401,11 @@
 end
 ```
 
 Note: This is not 100% the same as `NOT NULL` column constraint. Here’s a [good explanation](https://medium.com/doctolib/adding-a-not-null-constraint-on-pg-faster-with-minimal-locking-38b2c00c4d1c).
 
-### Using change_column_null with a default value (non-Postgres)
+### Using change_column_null with a default value
 
 #### Bad
 
 This generates a single `UPDATE` statement to set the default value.
 
@@ -427,10 +427,10 @@
     change_column_null :users, :some_column, false
   end
 end
 ```
 
-Note: In Postgres, `change_column_null` is still [not safe](#using-change_column_null) with this method.
+Note: In Postgres, `change_column_null` is still [not safe](#setting-not-null-on-an-existing-column) with this method.
 
 ### Adding a json column
 
 #### Bad