POD-823: Update docs

Readme.md

@@ -9,7 +9,9 @@ Dockerless is a tool that allows you to build and run Docker containers without
 
 ## Installation
 
-For example, to build an image:
+WARN: running dockerless on your host can delete key files and destroy your working environment.
+
+For example, to build an image, run the following in the gcr.io/kaniko-project/executor image:
 
 ``` bash
 dockerless build --dockerfile Dockerfile --context .
@@ -20,3 +22,13 @@ And to run a container:
 ``` bash
 dockerless start
 ```
+
+## Development
+
+Build dockerless and new image
+
+```bash
+just build
+cp dist/dockerless_{arch}/dockerless .
+docker build -t {repo}/dockerless:{tag} -f Dockerfile --build-arg TARGETARCH=$(uname -m) --build-arg TARGETOS=linux .
+```