README.md in strong_migrations-0.6.6 vs README.md in strong_migrations-0.6.7

@@ -19,10 +19,11 @@
 ```
 
 And run:
 
 ```sh
+bundle install
 rails generate strong_migrations:install
 ```
 
 ## Checks
 
@@ -38,12 +39,11 @@
 - [using change_column_null with a default value](#using-change_column_null-with-a-default-value)
 - [executing SQL directly](#executing-SQL-directly)
 
 Postgres-specific checks:
 
-- [adding an index non-concurrently](#adding-an-index)
-- [removing an index non-concurrently](#removing-an-index)
+- [adding an index non-concurrently](#adding-an-index-non-concurrently)
 - [adding a reference](#adding-a-reference)
 - [adding a foreign key](#adding-a-foreign-key)
 - [adding a json column](#adding-a-json-column)
 - [setting NOT NULL on an existing column](#setting-not-null-on-an-existing-column)
 
@@ -255,10 +255,12 @@
     end
   end
 end
 ```
 
+If you intend to drop an existing table, run `drop_table` first.
+
 ### Using change_column_null with a default value
 
 #### Bad
 
 This generates a single `UPDATE` statement to set the default value.
@@ -295,11 +297,11 @@
     safety_assured { execute "..." }
   end
 end
 ```
 
-### Adding an index
+### Adding an index non-concurrently
 
 #### Bad
 
 In Postgres, adding an index non-concurrently locks the table.
 
@@ -331,40 +333,10 @@
 
 ```sh
 rails g index table column
 ```
 
-### Removing an index
-
-Note: This check is [opt-in](#opt-in-checks).
-
-#### Bad
-
-In Postgres, removing an index non-concurrently locks the table for a brief period.
-
-```ruby
-class RemoveSomeIndexFromUsers < ActiveRecord::Migration[6.0]
-  def change
-    remove_index :users, :some_column
-  end
-end
-```
-
-#### Good
-
-Remove indexes concurrently.
-
-```ruby
-class RemoveSomeIndexFromUsers < ActiveRecord::Migration[6.0]
-  disable_ddl_transaction!
-
-  def change
-    remove_index :users, column: :some_column, algorithm: :concurrently
-  end
-end
-```
-
 ### Adding a reference
 
 #### Bad
 
 Rails adds an index non-concurrently to references by default, which is problematic for Postgres.
@@ -589,19 +561,15 @@
 
 Note: Since `remove_column` always requires a `safety_assured` block, it’s not possible to add a custom check for `remove_column` operations.
 
 ## Opt-in Checks
 
-Some operations rarely cause issues in practice, but can be checked if desired. Enable checks with:
+### Removing an index non-concurrently
 
-```ruby
-StrongMigrations.enable_check(:remove_index)
-```
+Postgres supports removing indexes concurrently, but removing them non-concurrently shouldn’t be an issue for most applications. You can enable this check with:
 
-To start a check only after a specific migration, use:
-
 ```ruby
-StrongMigrations.enable_check(:remove_index, start_after: 20170101000000)
+StrongMigrations.enable_check(:remove_index)
 ```
 
 ## Disable Checks
 
 Disable specific checks with: