Add ACME store

Signed-off-by: Emile Vauge <emile@vauge.com>

cluster/store.go

@@ -0,0 +1,16 @@
+package cluster
+
+// Object is the struct to store
+type Object interface{}
+
+// Store is a generic interface to represents a storage
+type Store interface {
+	Load() (Object, error)
+	Get() Object
+	Begin() (Transaction, Object, error)
+}
+
+// Transaction allows to set a struct in the KV store
+type Transaction interface {
+	Commit(object Object) error
+}