rudimentary docs

README.md

@@ -161,6 +161,63 @@ docker exec -it \
     <project-name>_erpnext-python_1 docker-entrypoint.sh migrate
 ```
 
+### Custom apps
+
+> For the sake of example, we'll be using a place holder called `[custom]`, and we'll be building off the edge image.
+
+To add your own apps to the image, we'll need to create a custom image with the help of a special wrapper script
+
+1. Create two folders called `[custom]-worker` and `[custom]-assets` in the `build` folder.
+
+  ```bash
+  cd frappe_docker
+  mkdir ./build/[custom]-worker ./build/[custom]-assets
+  ```
+
+2. Create a `Dockerfile` in `./build/[custom]-worker` with the following content:
+
+  ```Dockerfile
+  FROM frappe/erpnext-worker:edge
+
+  RUN install_app [custom] https://github.com/[username]/[custom] [branch]
+  # Only add the branch if you are using a specific tag or branch.
+  ```
+
+3. Create a `Dockerfile` in `./build/[custom]-assets` with the following content:
+
+  ```Dockerfile
+  FROM bitnami/node:12-prod
+
+  COPY build/[custom]-assets/install_app.sh /install_app
+
+  RUN /install_app [custom] https://github.com/[username]/[custom]
+
+  FROM frappe/erpnext-assets:edge
+
+  COPY --from=0 /home/frappe/frappe-bench/sites/ /var/www/html/
+  COPY --from=0 /rsync /rsync
+  RUN echo -n "\nerpnext" >> /var/www/html/apps.txt
+
+  VOLUME [ "/assets" ]
+
+  ENTRYPOINT ["/docker-entrypoint.sh"]
+  CMD ["nginx", "-g", "daemon off;"]
+  ```
+
+4. Copy over the `install_app.sh` file from `./build/erpnext-assets`
+
+  ```bash
+  cp ./build/erpnext-assets/install.sh ./build/[custom]-assets
+  ```
+
+5. Open up `./installation/docker-compose-custom.yml` and replace all instances of `[app]` with the name of your app.
+
+  ```bash
+  sed -i "s#\[app\]#[custom]#" ./installation/docker-compose-custom.yml
+  ```
+
+6. Install like usuall, except that when you set the `INSTALL_APPS` variable set it to `erpnext,[custom]`.
+
 ### Troubleshoot
 
 1. Remove containers and volumes, and clear redis cache: