Added readme instruction for ComposerKnowWhereCurrentFileIs function

Author: Simone Gentili

README.md

@@ -29,6 +29,13 @@ In this example after every `composer install` I exec a ctags generation
 This command open `composer.json`
 
 
+```vim
+:ComposerKnowWhereCurrentFileIs
+```
+This function aims to help you to load files without using ctag. Grep current word inside composer autogenerated files, and if only one occurrence is found, opens file in another tab. If zero or more occurrences are found, simply echoes a string to advice you. To use this in your .vimrc file, just remap function. For example you can use:
+map <F6>  :call ComposerKnowWhereCurrentFileIs()<CR>
+
+
 ## Install
 ```vim
 Bundle 'vim-php/vim-composer'