Update container usage documentation

README.md

@@ -21,6 +21,7 @@ limitations under the License.
 ![Celix MacOS](https://github.com/apache/celix/workflows/Celix%20MacOS/badge.svg)
 [![codecov](https://codecov.io/gh/apache/celix/branch/master/graph/badge.svg)](https://codecov.io/gh/apache/celix)
 [![Coverity Scan Build Status](https://scan.coverity.com/projects/6685/badge.svg)](https://scan.coverity.com/projects/6685)
+[![Gitpod ready-to-code](https://img.shields.io/badge/Gitpod-ready--to--code-blue?logo=gitpod)](https://gitpod.io/#https://github.com/apache/celix)
 
 Apache Celix is a framework for C, C++14 and C++17 to develop dynamic modular software applications using component 
 and in-process service-oriented programming. 

container/README.md

@@ -0,0 +1,53 @@
+# Celix dev container usage
+
+This subdirectory contains a [Containerfile](./Containerfile.gitpod) for developing on Celix locally or via Gitpod.
+Since the image is based on the Gitpod workspace image, it is also usable via https://gitpod.io/#https://github.com/apache/celix
+
+The below steps only need to be executed if you want to develop locally, and not via Gitpod.
+
+## Using a pre-built image
+
+### Start locally with sshd daemon
+
+```bash
+cd <project-root>
+
+# Start a local container with the SSH daemon running
+./container/start-gitpod-container.sh
+```
+
+Now connect to the container via the remote container option of your favoured IDE and start building/developing.
+
+### Start locally with only a bash shell
+
+The start script allows passing of additional paramters, which will override the starting of the SSH daemon.
+Execute the following commands to open a bash shell and build Celix from the command line:
+
+```bash
+cd <project-root>
+
+# Start a local container and open a bash shell
+./container/start-gitpod-container.sh bash
+
+# Build Apache Celix
+mkdir celix-build
+cd celix-build
+../container/support-scripts/build-all.sh
+make -j
+
+# Run the unit tests for Apache Celix
+ctest --output-on-failure
+```
+
+## Build the celix-dev image yourself
+
+```bash
+podman build -t docker.io/apache/celix-dev:$(date +%Y%m%d)-gitpod -f Containerfile.gitpod .
+```
+
+## Deploy a new celix-dev image (Celix PMC members only)
+
+```bash
+podman login docker.io
+podman push docker.io/apache/celix-dev:$(date +%Y%m%d)-gitpod
+```