1. Add a new step of cloning repo before building the docker image 2. Update the .gitignore file

Signed-off-by: kim-fitness <jianjin@cn.ibm.com>

.gitignore

@@ -7,6 +7,8 @@ placement
 *.dylib
 !vendor/**
 .idea
+_output
+
 # Test binary, built with `go test -c`
 *.test
 

README.md

@@ -21,6 +21,12 @@ You can reach the maintainers of this project at:
 
 You have at least one running kubernetes cluster;
 
+### Clone this repo
+```sh
+git clone https://github.com/open-cluster-management-io/placement.git
+cd placement
+```
+
 ### Deploy the placement controller
 Set environment variables.
 ```sh