Re-organise to use a bare repo

Re-organise to use a bare repo, e.g.
https://www.atlassian.com/git/tutorials/dotfiles.

.composer/.gitignore

@@ -0,0 +1,2 @@
+/.htaccess
+/cache/

.composer/composer.json

@@ -0,0 +1,16 @@
+{
+    "minimum-stability": "dev",
+    "prefer-stable": true,
+    "require": {
+        "deployer/deployer": "^4.0",
+        "drush/drush": "^8.0",
+        "hirak/prestissimo": "^0.3.5",
+        "laravel/installer": "^2.1",
+        "pantheon-systems/terminus": "^0.13.1",
+        "squizlabs/php_codesniffer": "^2.7",
+        "symfony/flex": "^1.6"
+    },
+    "config": {
+        "sort-packages": true
+    }
+}