update readme (#14)

Signed-off-by: rahul <rcsofttech85@gmail.com>

Author: rcsofttech85

.env renamed to .env.dist

@@ -1,3 +1,4 @@
 .idea
 .phpunit.cache
-vendor
+vendor
+.env

.gitignore

@@ -60,7 +60,7 @@ $fileHandler->open('file.txt');
 
 $fileHandler->open('php://stdout');
 
-fileHandler->write(data: "hello world");
+$fileHandler->write(data: "hello world");
 
 $fileHandler->close();
 
@@ -160,5 +160,17 @@ vendor/bin/file-diff oldFile newFile
 
 ```
 
+**File Integrity**
+
+```
+$fileHasher = new FileHashChecker();
+
+$fileHasher->hashFile(); 
+
+$fileHasher->verifyHash($fileHandlerObject,$hashListFileName);
+
+```
+
+