Update README.md

Author: xalopp

README.md

@@ -9,6 +9,21 @@ Requires
 * [PHP CodeSniffer](https://github.com/squizlabs/PHP_CodeSniffer)
 * [Symfony Coding Standard](https://github.com/xalopp/symfony-coding-standard)
 
+##MO4 Coding Standard
+
+The MO4 Coding Standard is an extension to the [Symfony Coding Standard](http://symfony.com/doc/current/contributing/code/standards.html) and adds following rules:
+
+* short tags "[...]" must be used instead of "array(...)",
+* in associates arrays, the "=>" operator must be aligned,
+* in arrays, the key and '=>' operator must be on the same line.
+* each consecutive variable assignements must align on gthe assigment operator,
+* use statements must be sorted,
+* you should use the imported class name, whenever it was imported with a use statement,
+* variables in double quoted strings must be surrounded by { }, e.g. "{$VAR}" instead of "$VAR",
+* sprintf or "{$VAR1} {$VAR2}" must be used insted of the concat operator, concat opetor are only allowed to concat constant an multi line strings,
+* a white space is requried after each cast opetor, e.g. "(int) $value" instead of "(int)$value",
+
+
 ## Installation
 
 1. Install phpcs: