FactoryGirl is a gem aimed at replacing Fixtures. If you wonder that, take a look at what's wrong with fixtures.

This is currently the most popular solution to serve rails apps and is used by many big companies like Github, tweet, 37signals and so on. Also, it is very easy to setup in this way.

每次都要查，真是蛋疼，不如一次性总结一下，以后再不记得就来这里找好了。以下代码中需要用到的文件名：filename = ‘testfile.txt’