Improve setup instructions in README (#151)

* Add COMPOSE_FILE env instructions to README

* minor edit

* Add link to dev containers install

README.md

@@ -50,7 +50,7 @@ Once you have one of these up and running, see the [Getting everything running](
 
 #### Using VS Code
 
-This project comes with a [devcontainer.json configuration](https://code.visualstudio.com/docs/devcontainers/containers) which can be used with VS Code. This takes care of all the `docker-compose` stuff in the background so you don't have to worry about it. When you open the project in VS Code, it should prompt you to start it in a dev container. Once the dev container starts, you can open a new terminal window in VS Code to run commands. See [the commands below](#getting-everything-running) for how to get everything started.
+This project comes with a [devcontainer.json configuration](https://code.visualstudio.com/docs/devcontainers/containers) which can be used with VS Code. This takes care of all the `docker-compose` stuff in the background so you don't have to worry about it. When you open the project in VS Code, it should prompt you to start it in a dev container (assuming [you've installed docker and the dev containers extension](https://code.visualstudio.com/docs/devcontainers/containers#_installation)). Once the dev container starts, you can open a new terminal window in VS Code to run commands. See [the commands below](#getting-everything-running) for how to get everything started.
 
 #### Using docker-compose directly
 
@@ -60,6 +60,15 @@ If you prefer not to use VS Code dev containers, the easiest way to develop in d
 docker-compose -f docker-compose.yml -f docker-compose.dev.yml up -d
 ```
 
+> **Note**
+> You can also set the `COMPOSE_FILE` environment variable to avoid having to specify the compose files every time. This one-liner will do that for you no matter which subdirectory you're in:
+>
+> ```
+> export COMPOSE_FILE=`git rev-parse --show-toplevel`/docker-compose.yml:`git rev-parse --show-toplevel`/docker-compose.dev.yml
+> ```
+>
+> After setting COMPOSE_FILE, you can just run `docker-compose up -d` from anywhere in the project.
+
 Once you have the services started, you can start a session inside the `web` container:
 
 ```
@@ -149,7 +158,6 @@ heroku run POOL_SIZE=2 iex -S mix
 
 The `POOL_SIZE` config var is necessary due to the current Postgres db having 20 connections. You can read more [about it here](https://hexdocs.pm/phoenix/heroku.html#creating-environment-variables-in-heroku).
 
-
 ## Emails
 
-Orcasite uses MJML for email templating. There are a few online MJML renderers, including: [mjml.io](https://mjml.io/try-it-live) and [grapes.js](https://grapesjs.com/demo-mjml.html)
+Orcasite uses MJML for email templating. There are a few online MJML renderers, including: [mjml.io](https://mjml.io/try-it-live) and [grapes.js](https://grapesjs.com/demo-mjml.html)