Creating tables and problems with primary key in Rails

I had a same problem before, and I solved according to here
https://github.com/rails/rails/pull/13247#issuecomment-32425844

With Rails 2.3.5, MySQL version 5.7.9 and mysql gem you need to have
this bit as an initializer in
config/initializers/abstract_mysql_adapter.rb:

class ActiveRecord::ConnectionAdapters::MysqlAdapter
  NATIVE_DATABASE_TYPES[:primary_key] = "int(11) auto_increment PRIMARY KEY"
end

For mysql2, it should be config/initializers/abstract_mysql2_adapter.rb:

class ActiveRecord::ConnectionAdapters::Mysql2Adapter
  NATIVE_DATABASE_TYPES[:primary_key] = "int(11) auto_increment PRIMARY KEY"
end