add git module add

Author: gkorland

.circleci/config.yml

@@ -9,7 +9,7 @@ jobs:
       - checkout
       - run:
           name: Install Submodules
-          command: git submodule sync && git submodule update --init
+          command: git submodule add  https://github.com/RedisLabsModules/redismodule-rs
       - run:
           name: Version information
           command: rustc --version; cargo --version; rustup --version