我使用命令：
$ rails g model Equipment
和rails执行了以下操作：

invoke  active_record
  create    db/migrate/20160822040448_create_equipment.rb
  create    app/models/equipment.rb
  invoke    test_unit
  create      test/models/equipment_test.rb
  create      test/fixtures/equipment.yml

正如你所看到的，迁移是单一的！因此，我将迁移文件和表名重命名为：

class CreateEquipments < ActiveRecord::Migration
  def change
    create_table :equipments do |t|
      # ...
    end
  end
end

现在，在运行$ rake db:migrate启动Rail的控制台$ rails c后，当我尝试启动一个Equipment时，它会出错，说它找不到表：

>> Equipment.new
PG::UndefinedTable: ERROR:  relation "equipment" does not exist
LINE 5:                WHERE a.attrelid = '"equipment"'::regclass
                                          ^
:               SELECT a.attname, format_type(a.atttypid, a.atttypmod),
                     pg_get_expr(d.adbin, d.adrelid), a.attnotnull, a.atttypid, a.atttypmod
                FROM pg_attribute a LEFT JOIN pg_attrdef d
                  ON a.attrelid = d.adrelid AND a.attnum = d.adnum
               WHERE a.attrelid = '"equipment"'::regclass
                 AND a.attnum > 0 AND NOT a.attisdropped
               ORDER BY a.attnum

ActiveRecord::StatementInvalid: PG::UndefinedTable: ERROR:  relation "equipment" does not exist
LINE 5:                WHERE a.attrelid = '"equipment"'::regclass
                                          ^
:               SELECT a.attname, format_type(a.atttypid, a.atttypmod),
                     pg_get_expr(d.adbin, d.adrelid), a.attnotnull, a.atttypid, a.atttypmod
                FROM pg_attribute a LEFT JOIN pg_attrdef d
                  ON a.attrelid = d.adrelid AND a.attnum = d.adnum
               WHERE a.attrelid = '"equipment"'::regclass
                 AND a.attnum > 0 AND NOT a.attisdropped
               ORDER BY a.attnum

我可以通过在模型中添加以下行来修补它：

class Equipment < ActiveRecord::Base
        self.table_name = 'equipments'
        # ...
    end

但是，虽然这解决了问题，我想知道是什么导致的问题开始。
最后一点：我试着在控制台上运行#pluralize方法，它也不会对字符串'Equipment'进行复数化：

>> 'Equipment'.pluralize
=> "Equipment"
>> 'door'.pluralize
=> "doors"