Update README.md

Author: Blinnikov

README.md

@@ -1,2 +1,58 @@
 # gulp-main-node-files
-Allows to get main js files from installed node modules
+Allows to get main js files from installed ```/node_modules```.
+``` javascript
+var files = gulpMainNodeFiles([options]);
+```
+
+## Installation
+
+```
+npm i --save-dev gulp-main-node-files
+```
+
+## Usage
+- Connect in ```gulpfile.js```
+
+```javascript
+var mainNodeFiles = require('gulp-main-node-files');
+```
+  and than
+``` javascript
+var mainNodeJsFiles = mainNodeFiles();
+var src = gulp.src(mainNodeJsFiles, { base: '.' });
+```
+
+- For example, copying js-files from ```/node_modules``` folder to ```/build```.
+``` javascript
+gulp.src(mainNodeFiles(), { base: '.' })
+    .pipe(gulp.dest('./build'));
+```
+
+## Options
+You can pass in the ```options``` object to customize function behavior with the following keys:
+
+- **packageJsonPath** (default - ``` './package.json' ``` ) - a path to your ```package.json``` file.
+
+- **nodeModulesPath** (default - ```'./node_modules'```) - a path to ```node_modules``` folder.
+
+- **overrides** (no default value) - this is an object that allows override ```main:``` section from ```package.json``` file.
+  - For example, if package points out to the wrong or not the whole-source file:
+    ``` javascript
+    mainNodeFiles({
+      overrides: {
+        'packery': 'dist/packery.pkgd.js'
+      }
+    }
+    ```
+  - or if you want to return several main files:
+  ``` javascript
+  mainNodeFiles({
+    overrides: {
+      'codemirror': [
+        'lib/codemirror.js',
+        'mode/clike/clike.js',
+        'addon/edit/closebrackets.js',
+      ]
+    }
+  })
+  ```