add vault/etcd

config/source/vault/README.md

@@ -0,0 +1,43 @@
+# Vault Source
+
+The vault source reads config from different secret engines in a Vault server. For example:
+```
+kv: secret/data/<my/secret>
+database credentials: database/creds/<my-db-role>
+```
+
+## New Source
+
+Specify source with data
+
+```go
+vaultSource := vault.NewSource(
+	// mandatory: it specifies server address. 
+	// It could have different formats:
+	// 127.0.0.1 -> https://127.0.0.1:8200
+	// http://127.0.0.1 -> http://127.0.0.1:8200
+	// http://127.0.0.1:2233
+	vault.WithAddress("http://127.0.0.1:8200"),
+	// mandatory: it specifies a resource to been access
+	vault.WithResourcePath("secret/data/my/secret"),
+    // mandatory: it specifies a resource to been access
+	vault.WithToken("<my-token>"),
+	// optional: path to store my secret.
+	// By default use resourcePath value 
+	vault.WithSecretName("my/secret"),
+	// optional: namespace.
+    vault.WithNameSpace("myNameSpace"),
+)
+```
+
+## Load Source
+
+Load the source into config
+
+```go
+// Create new config
+conf := config.NewConfig()
+
+// Load file source
+conf.Load(vaultSource)
+```