Add profiles documentation

plugins/profiles/README.md

+# profiles plugin
+
+This plugin allows you to create separate configuration files for zsh based
+on a domain of your host.
+
+It takes your `HOST` and looks for files named according to the domain parts 
+in `$ZSH_CUSTOM/profiles/` directory.
+
+For example, for `HOST=my.domain.com`, it will try to load the following files:
+
+```text
+$ZSH_CUSTOM/profiles/my.domain.com
+$ZSH_CUSTOM/profiles/domain.com
+$ZSH_CUSTOM/profiles/com
+```
+
+To use it, add profiles to the plugins array of your zshrc file:
+
+```sh
+plugins=(... profiles)
+```