Add README

README.md

@@ -1,2 +1,34 @@
 # dom-helpers
+
 Helper functions for faster DOM scripting
+
+## Install
+
+```
+yarn add @three11/dom-helpers
+```
+
+or
+
+```
+npm i @three11/dom-helpers
+```
+
+## Usage
+
+```
+import * as helpers from '@three11/dom-helpers';
+```
+
+or
+
+Import each function separately.
+
+See functions list below.
+
+## Functions
+
+* `byID` - retrieves an element by ID
+* `single` - retrieves an element by a given valid css selector
+* `multi` - retrieves a collection of elements and normalizes the return value
+* `addListener` - attaches an event listener to element