update repo branch structure in README

Author: trevorcampbell

README.md

@@ -17,10 +17,10 @@ See [the license file](LICENSE.md) for more information.
 Building the book requires Docker (instructions here: [https://docs.docker.com/get-docker/](https://docs.docker.com/get-docker/)).
 
 ### Contributing 
-Primary development in this repository happens on the `dev` branch. If you want to contribute to the book,
-please branch off of `dev` and make a pull request into `dev`.
+Primary development in this repository happens on the `main` branch. If you want to contribute to the book,
+please branch off of `main` and make a pull request into `main`.
 
-The `main` branch contains the source material for the live, publicly viewable HTML book.
+The `production` branch contains the source material for the live, publicly viewable HTML book.
 
 ### Build locally
 
@@ -32,13 +32,13 @@ in the root directory of this repository. The book can be viewed in your browser
 
 ### Update build environment
 
-You can update the build environment for the book by making changes to `Dockerfile` in the root of the repository in the `dev` branch.
-If you push any changes to the `Dockerfile` on the `dev` branch, GitHub will trigger a rebuild of the docker image,
+You can update the build environment for the book by making changes to `Dockerfile` in the root of the repository in the `main` branch.
+If you push any changes to the `Dockerfile` on the `main` branch, GitHub will trigger a rebuild of the docker image,
 push it to DockerHub, and update the `build_html.sh` script and book deploy GitHub action with the new image tag.
 
 ### Update public html
 
-You can update the live, publicly viewable HTML book by making changes to the `source/` folder in the `main` branch.
-If you push any changes to the `source/` folder on the `main` branch, GitHub will trigger a rebuild of the public HTML site.
+You can update the live, publicly viewable HTML book by making changes to the `source/` folder in the `production` branch.
+If you push any changes to the `source/` folder on the `production` branch, GitHub will trigger a rebuild of the public HTML site.