Difference between #3 and #4 of how to use github (un)official extension repo in your Yii project

how to use github (un)officialofficial extension repo in
your Yii project

Using a git submodule command in your yii project
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I'mIm developing a web project for a company
using Yiiwith yii framework. We are using a git
vcs in our development process.
We 
We like to use Yiiyii extensions. But only if they
are good. 

We are very carefully chossing an extension very
carefully.extension, if we need something. If we don't like
itsan extension code or something else, we
don'twedon't use it.that extension. And
last time someone noticed, that we are using only extensions from
[(un)official[official github yii extensions
repo](https://github.com/yiiext) . But we still need a solution how to use that
repositoires independently from our project ?

~~~
git submodule add https://github.com/yiiext/with-related-behavior
./protected/extensions/
~~~

This command will add an extension repository under our project extension
folder. And any other extension from github
(un)officialofficial yii extension repo you can add to
your project git repo easy. 
Then when another coder cloned your repo his extension folders will be empty. He
needs to type 
~~~
git submodule update --init --recursive
~~~
And then extensions will appear in his repo too. 


very nice feature. You can read more about it on
[Progit](http://progit.org/book/ch6-6.html)