📝 Update README.

README.md

@@ -20,6 +20,104 @@ Include composer autoloader in your main file (Ex.: index.php)
 
 - `require __DIR__.'/../vendor/autoload.php';`
 
+This package gives you the ability to convert XML string/file to JSON string/file.  
+For this, we have two converters:
+- `ABGEO\XmlToJson\StringConverter`
+- `ABGEO\XmlToJson\FileConverter`
+
+Let's look at them in action.
+
+### Convert XML String to JSON string
+
+Create simple XML file:
+
+`example.xml`
+```xml
+<?xml version="1.0" encoding="UTF-8"?>
+<profile>
+    <firstName>Temuri</firstName>
+    <lastName>Takalandze</lastName>
+    <active>true</active>
+    <position>
+        <title>Developer</title>
+        <department>
+            <title>IT</title>
+        </department>
+    </position>
+</profile>
+```
+
+Create an object of class `ABGEO\XmlToJson\StringConverter` and read the content of `example.xml` into a variable:
+
+```php
+$converter = new StringConverter();
+$xmlContent = file_get_contents(__DIR__ . '/example.xml');
+```
+
+Now you can convert value of `$xmlContent` variable to JSON object:
+
+```php
+$jsonContent = $converter->convert($xmlContent);
+```
+
+if you print this variable, you will get the following result:
+
+```php
+echo $jsonContent;
+
+//{
+//    "profile": {
+//    "firstName": "Temuri",
+//        "lastName": "Takalandze",
+//        "active": "true",
+//        "position": {
+//        "title": "Developer",
+//            "department": {
+//            "title": "IT"
+//            }
+//        }
+//    }
+//}
+```
+
+### Convert XML file to JSON file
+
+Consider that you already have the `example.xml` file described in the step above. Now let's create 
+an object of `ABGEO\XmlToJson\FileConverter` class:
+
+
+```php
+$converter = new FileConverter();
+```
+
+Using the `convert` method of this object, you can simply convert the XML file to a JSON file:
+
+```php
+$converter->convert(__DIR__ . '/example.xml', __DIR__ . '/example.json');
+```
+
+`Convert()` takes two arguments - the path to the input and output files. 
+If you do not specify an output file, by default it will be {$inputFile}.json.
+
+Finally, the `Convert ()` method will generate a new `example.json` with the following content:
+
+`example.json`
+```json
+{
+    "profile": {
+        "firstName": "Temuri",
+        "lastName": "Takalandze",
+        "active": "true",
+        "position": {
+            "title": "Developer",
+            "department": {
+                "title": "IT"
+            }
+        }
+    }
+}
+```
+
 **See full example [here](examples).**
 
 ## Changelog