Add 30 seconds of PHP code

[sohelamin]

This repo will help the newcomers or anyone else to understand PHP snippets in just 30 seconds.

[VarCI-bot]

This pull request adds the following suggestion:

• 30 Seconds of PHP Code - A curated collection of useful PHP snippets that you can understand in 30 seconds or less.

-- Automated response by Var.CI :robot:

[VarCI-bot]

@sohelamin, please update the pull request body with a description of what you are adding or changing (of at least 25 characters).

-- Automated response by Var.CI :robot:

[ziadoz]

Thanks for your suggestion.