Rename CompatibleMigration -> Migration

spec/migrations/1_create_authors_table.rb

@@ -1,4 +1,4 @@
-class CreateAuthorsTable < CompatibleMigration
+class CreateAuthorsTable < Migration
   def change
     create_table :authors do |t|
       t.string :name, null: false

spec/migrations/2_create_books_table.rb

@@ -1,4 +1,4 @@
-class CreateBooksTable < CompatibleMigration
+class CreateBooksTable < Migration
   def change
     create_table :books do |t|
       if ActiveRecord::VERSION::STRING >= "5.0.0"

spec/migrations/3_add_constraints.rb

@@ -1,4 +1,4 @@
-class AddConstraints < CompatibleMigration
+class AddConstraints < Migration
   def change
     add_foreign_key_constraint :books, :authors, on_delete: :cascade, index: true
     add_presence_constraint :books, :title

spec/migrations/4_create_books_per_author_view.rb

@@ -1,4 +1,4 @@
-class CreateBooksPerAuthorView < CompatibleMigration
+class CreateBooksPerAuthorView < Migration
   def change
     create_view(
       :books_per_author,

spec/spec_helper.rb

@@ -1,7 +1,7 @@
 $LOAD_PATH.unshift File.expand_path("../../lib", __FILE__)
 
 require "rein"
-require "support/compatible_migration"
+require "support/migration"
 
 MIGRATIONS_PATH = [File.expand_path("../migrations", __FILE__)].freeze
 

spec/support/migration.rb

@@ -0,0 +1,8 @@
+# Support the new rails 5 migration syntax, while retaining backwards
+# compatibility with the old sytax.
+Migration = # rubocop:disable Naming/ConstantName
+  if ActiveRecord::VERSION::STRING >= "5.0.0"
+    ActiveRecord::Migration["#{ActiveRecord::VERSION::MAJOR}.#{ActiveRecord::VERSION::MINOR}"]
+  else
+    ActiveRecord::Migration
+  end