some docs

README.md

@@ -1,2 +1,14 @@
 # Vault Unsealer
-This is a simple Rust program that automatically unseals a hashicorp vault instance
+This is a simple Rust program that automatically unseals a hashicorp vault instance.
+
+| :exclamation: this method of unsealing the vault is not recommended if you have high security requirements!  |
+|-----------------------------------------|
+
+
+## Environment Variables
+
+| env var    | default | description |
+| ---------- | ------- | ----------- |
+| VAULT_ADDR |    -    | address of the vault server |
+| VAULT_KEY_FILE | - | json file containing vault unseal key(s), see [./example_keys.json](./example_keys.json) |
+| UNSEAL_INTERVAL | 15 | seconds to wait between checks / unseal attempts |

example_keys.json

@@ -0,0 +1,7 @@
+{
+    "keys": [
+        "a",
+        "b",
+        "c"
+    ]
+}