Change install generator to use new hash syntax

The install generator used literal Ruby hashes to build options for the
item_type field.  This change modifies the generator to use string
literal output, which is consistent with the other option building method
in the generator.

Co-authored-by: Jared Beck <jared@jaredbeck.com>

lib/generators/paper_trail/install/install_generator.rb

@@ -40,9 +40,11 @@ module PaperTrail
     # MySQL 5.6 utf8mb4 limit is 191 chars for keys used in indexes.
     # See https://github.com/paper-trail-gem/paper_trail/issues/651
     def item_type_options
-      opt = { null: false }
-      opt[:limit] = 191 if mysql?
-      ", #{opt}"
+      if mysql?
+        ", { null: false, limit: 191 }"
+      else
+        ", { null: false }"
+      end
     end
 
     def mysql?

spec/generators/paper_trail/install_generator_spec.rb

@@ -35,6 +35,13 @@ RSpec.describe PaperTrail::InstallGenerator, type: :generator do
           ""
         end
       }.call
+      expected_item_type_options = lambda {
+        if described_class::MYSQL_ADAPTERS.include?(ActiveRecord::Base.connection.class.name)
+          ", { null: false, limit: 191 }"
+        else
+          ", { null: false }"
+        end
+      }.call
       expect(destination_root).to(
         have_structure {
           directory("db") {
@@ -43,6 +50,7 @@ RSpec.describe PaperTrail::InstallGenerator, type: :generator do
                 contains("class CreateVersions < " + expected_parent_class)
                 contains "def change"
                 contains "create_table :versions#{expected_create_table_options}"
+                contains "  t.string   :item_type#{expected_item_type_options}"
               }
             }
           }