Merge pull request #2718 from qiansen1386/patch-2

docs/guide/composer.md

 Composer
 ========
 
-Yii2 uses Composer as its package manager. Composer is a PHP utility that can automatically handle the installation of needed libraries and
+Yii2 uses Composer as its dependency management tool. Composer is a PHP utility that can automatically handle the installation of needed libraries and
 extensions, thereby keeping those third-party resources up to date while absolving you of the need to manually manage the project's dependencies.
 
 Installing Composer
@@ -97,4 +97,4 @@ Either install git or try adding `--prefer-dist` to the end of `install` or `upd
 See also
 --------
 
-- [Official Composer documentation](http://getcomposer.org).
\ No newline at end of file
+- [Official Composer documentation](http://getcomposer.org).