docs: more developer setup documentation

Covers direnv, and warnings in rtx.

docs/developer-setup.md

@@ -19,7 +19,14 @@ brew install --cask 1password/tap/1password-cli
 Once 1password-cli is installed you can verify the installation using:
 ```shell
+# Check that version >= 2
 op --version
+
+# Ensure that you are signed into GitLab
+eval $(op signin --account gitlab.1password.com)
+
+# Check that the connection is working
+op vault list
 ```
 **Note: v2 of the 1password-cli is required.**
@@ -103,6 +110,9 @@ Linux users should follow the instructions for their package manager in [the rtx
 Once you've installed `rtx`, add the following line to your shell. Remember to restart your terminal for the change to take affect.
 ```shell
+# Disable the `legacy_version_file` feature for rtx
+rtx settings set legacy_version_file false
+
 # bash
 echo 'eval "$('$(which rtx)' activate bash)"' >> ~/.bashrc
 # zsh
@@ -113,6 +123,29 @@ echo 'rtx activate fish | source' >> ~/.config/fish/config.fish
 Did you remember to restart your terminal? Good.
+#### Step 3.4: Setup `direnv`
+
+>>>
+`direnv` is an extension for your shell. It augments existing shells with a new feature that can load and unload environment variables depending on the current directory.
+>>>
+
+Follow the `direnv` [installation documentation](https://github.com/direnv/direnv/blob/master/docs/installation.md). For macOS, you can use:
+
+```shell
+brew install direnv
+```
+
+Next, you'll need to hook `direnv` into your shell.
+
+```shell
+# bash
+echo 'eval "$(direnv hook bash)"' >> ~/.bashrc
+# zsh
+echo 'eval "$(direnv hook zsh)"' >> ~/.zshrc
+```
+
+For other shells, follow the instructions at <https://github.com/direnv/direnv/blob/master/docs/hook.md>.
+
 ### Step 2: Install development dependencies
 Install all the plugins by running: