Added sample way of using this module

Author: ntmspavan

README.md

@@ -1,2 +1,31 @@
-# terraform-aws-kms-share-multi-accounts
-module to create kms key and share the access to multi accounts with IAM and Users
+# *Terraform-aws-kms-share-multi-accounts*
+module to create custom kms key and share access to multiple AWS accounts with option to add  particular IAM Roles and Users
+## Sample way of using this module
+> There are 2 ways to use this module.
+
+1. Using default policy to create kms key and share to dest accounts
+
+```
+module "kms_sharing" {
+  source           = "[email protected]:devops-made-easy/terraform-aws-kms-share-multi-accounts.git"
+  version          = "1.0.0"
+  key_name         = "devops-key-sharing"
+  dest_account_ids = ["1111111", "222222", "333333"]
+  dest_iam_roles   = ["arn:aws:iam::xxxxxx:role/dest_iam_role"](optional)
+  src_account_ids  = ["444444"]
+  src_iam_roles   = ["arn:aws:iam::xxxxxx:role/src_iam_role"](optional)
+}
+```
+2. Using Custom policy provided to this module 
+```
+module "kms_sharing" {
+  source           = "[email protected]:devops-made-easy/terraform-aws-kms-share-multi-accounts.git"
+  version          = "1.0.0"
+  key_name         = "devops-key-sharing"
+  dest_account_ids = ["1111111", "222222", "333333"]
+  dest_iam_roles   = ["arn:aws:iam::xxxxxx:role/dest_iam_role"](optional)
+  src_account_ids  = ["444444"]
+  src_iam_roles   = ["arn:aws:iam::xxxxxx:role/src_iam_role"](optional)
+  user_policy      = file("${path.module}/xxxx.json.tpl")(optional)
+}
+```