refactor: minor doc changes

README.md

@@ -13,7 +13,7 @@ go get github.com/rhnvrm/simples3
 ## Example
 
 ```go
-testTxt, _ := os.Open("test.txt")
+testTxt, _ := os.Open("testdata/test.txt")
 defer testTxt.Close()
 
 // Create an instance of the package
@@ -24,6 +24,9 @@ s3 := simples3.New(Region, AWSAccessKey, AWSSecretKey)
 // obtain credentials from IAM attached to the instance.
 s3 := simples3.NewUsingIAM(Region)
 
+// You can also set a custom endpoint to a compatible s3 instance. 
+s3.SetEndpoint(CustomEndpoint)
+
 // Note: Consider adding a testTxt.Seek(0, 0)
 // in case you have read 
 // the body, as the pointer is shared by the library.