diff --git a/lib/rails/generators/mobility/templates/column_translations.rb b/lib/rails/generators/mobility/templates/column_translations.rb
index b73f236bc..3e35f6d3d 100644
--- a/lib/rails/generators/mobility/templates/column_translations.rb
+++ b/lib/rails/generators/mobility/templates/column_translations.rb
@@ -4,7 +4,7 @@ def change
 <% I18n.available_locales.each do |locale| -%>
 <% column_name = Mobility.normalize_locale_accessor(attribute.name, locale) -%>
 <% if connection.column_exists?(table_name, column_name) -%>
-<% warn "#{column_name} already exists, skipping." %>
+<% warn "#{column_name} already exists, skipping." -%>
 <% else -%>
     add_column :<%= table_name %>, :<%= column_name %>, :<%= attribute.type %><%= attribute.inject_options %>
     <%- if attribute.has_index? -%>
diff --git a/lib/rails/generators/mobility/templates/table_migration.rb b/lib/rails/generators/mobility/templates/table_migration.rb
index 3620c9422..89cb1839f 100644
--- a/lib/rails/generators/mobility/templates/table_migration.rb
+++ b/lib/rails/generators/mobility/templates/table_migration.rb
@@ -9,7 +9,7 @@ def change
   <%- else -%>
     add_column :<%= table_name %>, :<%= attribute.name %>, :<%= attribute.type %><%= attribute.inject_options %>
     <%- if attribute.has_index? -%>
-    add_index :<%= table_name %>, :<%= attribute.index_name %><%= attribute.inject_index_options %>
+    add_index :<%= table_name %>, [:<%= attribute.index_name %><%= attribute.inject_index_options %>, :locale]
     <%- end -%>
   <%- end -%>
 <% end -%>
diff --git a/lib/rails/generators/mobility/templates/table_translations.rb b/lib/rails/generators/mobility/templates/table_translations.rb
index e001e9498..4c39a2586 100644
--- a/lib/rails/generators/mobility/templates/table_translations.rb
+++ b/lib/rails/generators/mobility/templates/table_translations.rb
@@ -22,7 +22,7 @@ def change
     add_index :<%= table_name %>, [:<%= foreign_key %>, :locale], name: :<%= translation_unique_index_name %>, unique: true
 
 <%- attributes_with_index.each do |attribute| -%>
-    add_index :<%= table_name %>, :<%= attribute.index_name %><%= attribute.inject_index_options %>
+    add_index :<%= table_name %>, [:<%= attribute.index_name %><%= attribute.inject_index_options %>, :locale]
 <%- end -%>
   end
 end
diff --git a/lib/rails/generators/mobility/translations_generator.rb b/lib/rails/generators/mobility/translations_generator.rb
index b149710cc..69df2f15c 100644
--- a/lib/rails/generators/mobility/translations_generator.rb
+++ b/lib/rails/generators/mobility/translations_generator.rb
@@ -29,16 +29,17 @@ module Mobility
 Other backends are not supported, for obvious reasons:
 * the +key_value+ backend does not need any model-specific migrations, simply
   run the install generator.
-* +jsonb+, +hstore+ and +serialized+ backends simply require a single column on
-  a model table, which can be added with the normal Rails migration generator.
+* +json+, +jsonb+, +hstore+, +serialized+, and +container+ backends simply
+  require a single column on a model table, which can be added with the normal
+  Rails migration generator.
 
 =end
   class TranslationsGenerator < ::Rails::Generators::NamedBase
-    SUPPORTED_BACKENDS = %w[column table]
-    BACKEND_OPTIONS = { type: :string, desc: "Backend to use for translations (defaults to Mobility.default_backend)" }
+    SUPPORTED_BACKENDS = %w[column table].freeze
+    BACKEND_OPTIONS = { type: :string, desc: "Backend to use for translations (defaults to Mobility.default_backend)" }.freeze
     argument :attributes, type: :array, default: [], banner: "field[:type][:index] field[:type][:index]"
 
-    class_option(:backend, BACKEND_OPTIONS)
+    class_option(:backend, BACKEND_OPTIONS.dup)
     invoke_from_option :backend
 
     def self.class_options(options = nil)
diff --git a/spec/generators/rails/mobility/translations_generator_spec.rb b/spec/generators/rails/mobility/translations_generator_spec.rb
index 9f3d6daca..3cf9ff13b 100644
--- a/spec/generators/rails/mobility/translations_generator_spec.rb
+++ b/spec/generators/rails/mobility/translations_generator_spec.rb
@@ -40,7 +40,7 @@
                 contains "add_index :post_translations, :post_id, name: :index_post_translations_on_post_id"
                 contains "add_index :post_translations, :locale, name: :index_post_translations_on_locale"
                 contains "add_index :post_translations, [:post_id, :locale], name: :index_post_translations_on_post_id_and_locale, unique: true"
-                contains "add_index :post_translations, :title"
+                contains "add_index :post_translations, [:title, :locale]"
               end
             end
           end
@@ -66,7 +66,7 @@
                   contains "class CreatePostTitleAndContentTranslationsForMobilityTableBackend < ActiveRecord::Migration[#{version_string_}]"
                 end
                 contains "add_column :post_translations, :title, :string"
-                contains "add_index :post_translations, :title"
+                contains "add_index :post_translations, [:title, :locale]"
                 contains "add_column :post_translations, :content, :text"
               end
             end