chore: reformat go, add commitizen for commit message

.pre-commit-config.yaml

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 11e24bd..7660034 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,15 +1,33 @@
+# See instructions in CONTRIBUTING.md
+# See https://pre-commit.com for more information
+# See https://pre-commit.com/hooks.html for more hooks
 repos:
-  - repo: https://github.com/syntaqx/git-hooks 
+  # Locally-authored hooks for better hermeticity
+  - repo: local 
+    hooks:
+    - id: go-fmt
+      name: go fmt
+      description: Runs `go fmt` and asserts no changes are needed.
+      entry: ./hooks/go-fmt.sh
+      language: script
+      files: \.go$
+  - repo: https://github.com/syntaqx/git-hooks
     rev: v0.0.17
     hooks:
+    # Requires that shellcheck is already installed
     - id: shellcheck
-    - id: go-fmt
+  - repo: https://github.com/commitizen-tools/commitizen
+    rev: v2.18.0
+    hooks:
+      # Requires that commitizen is already installed
+      - id: commitizen
+        stages: [commit-msg]
   - repo: https://github.com/keith/pre-commit-buildifier
     rev: 4.0.1.1
     hooks:
+      # Requires that buildifier is already installed
       - id: buildifier
         args: &args
-          # Keep this argument in sync with .bazelci/presubmit.yaml
           - --warnings=all
       - id: buildifier-lint
         args: *args
\ No newline at end of file

CONTRIBUTING.md

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
new file mode 100644
index 0000000..597ead9
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1,14 @@
+Want to contribute? Great!
+
+## Formatting/linting
+
+We suggest using a pre-commit hook to automate this.
+First [install pre-commit](https://pre-commit.com/#installation),
+then run
+
+```shell
+pre-commit install
+pre-commit install --hook-type commit-msg
+```
+
+Otherwise the CI will yell at you about formatting/linting violations.

cmd/root.go

diff --git a/cmd/root.go b/cmd/root.go
index a8e545d..430dc8a 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -10,10 +10,10 @@
 	"github.com/spf13/cobra"
 	"os"
 
+	"github.com/fatih/color"
+	"github.com/mattn/go-isatty"
 	homedir "github.com/mitchellh/go-homedir"
 	"github.com/spf13/viper"
-	"github.com/mattn/go-isatty"
-	"github.com/fatih/color"
 )
 
 var cfgFile string

hooks/go-fmt.sh

diff --git a/hooks/go-fmt.sh b/hooks/go-fmt.sh
new file mode 100755
index 0000000..fdc14c7
--- /dev/null
+++ b/hooks/go-fmt.sh
@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+set -e
+
+output="$(bazel 2>/dev/null run -- @go_sdk//:bin/gofmt -l "$@")"
+
+[[ -z "$output" ]] && exit 0
+
+echo >&2 "Go files must be formatted with gofmt. Please run:"
+for f in $output; do
+  echo >&2 "  bazel run -- @go_sdk//:bin/gofmt -w $PWD/$f"
+done
+
+exit 1