add call op type

Author: sevenbitbyte

src/comms/protocol-scheme.js

@@ -7,6 +7,7 @@ const OP_HEADER = Joi.object().keys({
   id: ID_SCHEME.required(),
   op: Joi.string().valid([
     'auth',
+    'call',
     'advertise',
     'subscribe',
     'unsubscribe',
@@ -21,6 +22,11 @@ const AUTH_OP = Joi.object().keys({
   session: Joi.objectId().required()
 })
 
+const CALL_OP = Joi.object().keys({
+  id: ID_SCHEME.required(),
+  op: Joi.string().valid('call').required()
+})
+
 const ADVERTISE_OP = Joi.object().keys({
   id: ID_SCHEME.required(),
   op: Joi.string().valid('advertise').required(),