Added "Codeigniter framework" (#28422)

* Added "Codeigniter framework"

Codeigniter is a popular php framework. So I have added a file about it.

* fixed Uppercase name

fixed Uppercase name

* fix: add front matter block

guide/english/codeigniter/index.md

@@ -0,0 +1,32 @@
+---
+title: Codeigniter
+---
+
+# Codeigniter
+
+CodeIgniter is a powerful PHP framework with a very small footprint, built for developers who need a simple and elegant toolkit to create full-featured web applications.
+ [Wikipedia](https://en.wikipedia.org/wiki/CodeIgniter)
+
+# Who is CodeIgniter For?
+CodeIgniter is right for you if:
+
+* You want a framework with a small footprint.
+* You need exceptional performance.
+* You need broad compatibility with standard hosting accounts that run a variety of PHP versions and configurations.
+* You want a framework that requires nearly zero configuration.
+* You want a framework that does not require you to use the command line.
+* You want a framework that does not require you to adhere to restrictive coding rules.
+* You are not interested in large-scale monolithic libraries like PEAR.
+* You do not want to be forced to learn a templating language (although a template parser is optionally available if you desire one).
+* You eschew complexity, favoring simple solutions.
+* You need clear, thorough documentation.
+
+## CodeIgniter 3.x
+CodeIgniter 3.x is licensed under the [MIT License](https://codeigniter.com/user_guide/license.html).
+
+User guide : [Link](https://codeigniter.com/user_guide/)
+
+## CodeIgniter 2.x
+CodeIgniter 2.x is licensed under the [EllisLab open source license](https://codeigniter.com/userguide2/license.html).
+
+User guide : [Link](https://codeigniter.com/userguide2/)