Create cli-porter-deploy.md as a WIP

docs/reference/cli-porter-deploy.md

@@ -0,0 +1,44 @@
+> 🚧 Beta Notice
+> 
+> **Note:** `porter deploy` was introduced in version `0.4.0` and is currently in `beta`, thus it is subject to change and may not work reliably. If you encounter an error, please [file a bug report](https://github.com/porter-dev/porter/issues/new?assignees=&labels=&template=bug.md). 
+
+Version `0.4.0` of Porter added supported for building and re-deploying an existing application using the Porter CLI. For example, the following command will re-deploy an application called `example-app` from the most recent Github commit in the specified branch/repository:
+
+```sh
+porter deploy --app example-app
+```
+
+The default behavior of `porter deploy` is to **use the remote repository as the source of truth**. If you would like to use a local directory (such as your current working directory) as the directory to build from, go to the [deploying from local source]() section.
+
+By default, this command performs four steps: gets the environment variables for the application, builds a new Docker container from the source files, pushes a new Docker image to the remote registry, and calls the Porter webhook to re-deploy the application. However, we designed this command to be modular: if you would like to add intermediate steps in your own build process, you can call different `porter deploy` sub-commands separately:
+
+- `porter deploy get-env` - prints the build environment variables to the terminal or a file.  
+- `porter deploy build` - builds the Docker container used for deployment.
+- `porter deploy push` - pushes the Docker container used for deployment to a remote registry.
+- `porter deploy call-webhook` - calls the Porter webhook to trigger a re-deploy of the application. 
+
+To see a working example, check out the [creating a custom CI pipeline]() guide.
+
+### `porter deploy`
+
+### `porter deploy get-env`
+
+### `porter deploy build`
+
+### `porter deploy push`
+
+### `porter deploy call-webhook`
+
+## Deploying from Local Source
+
+You can choose to deploy from your local filesystem by using the `--local` flag:
+
+```sh
+porter deploy --app example-app --local
+```
+
+This will by default read from the directory that the `porter` command is called from. If you would like to specify a different directory, use the `--path` flag:
+
+```sh
+porter deploy --app example-app --local --path ~/porter/porter-example
+```