Adding parameter for authentication method.

Author: itouri

model/model.pb.go

@@ -117,6 +117,12 @@ message LxcTemplate {
   }
   Template lxc_template = 7 [json_name="lxc_template"];
   repeated string node_groups = 8 [json_name="node_groups"];
+  enum AuthenticationType {
+    NONE = 0;
+    PUB_KEY = 1;
+  }
+  AuthenticationType authentication_type = 9 [json_name="authentication_type"];
+  string ssh_public_key = 10 [json_name="ssh_public_key"];
 }
 
 message NullTemplate {