feat: add ability to initialize a git repository out of band

This is useful in contexts where the repository directory may be created and interacted with via git-http-backend or other methods of updating a repository.

plugins/git/subcommands/initialize

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+source "$PLUGIN_CORE_AVAILABLE_PATH/common/functions"
+source "$PLUGIN_AVAILABLE_PATH/git/functions"
+set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
+
+git-initialize-cmd() {
+  declare desc="initialize a git repository for an app"
+  local cmd="git:initialize" argv=("$@"); [[ ${argv[0]} == "$cmd" ]] && shift 1
+  declare APP="$1"
+  is_valid_app_name "$APP"
+
+  dokku_log_info1_quiet "Initializing git repository for $APP"
+  fn-git-create-hook "$APP"
+}
+
+git-initialize-cmd "$@"