Added composer.json

Once we've sorted out packagist listing ownership,
we should be able to remove the custom repository entries.

composer.json

@@ -0,0 +1,21 @@
+{
+	"name": "silverstripe/installer",
+	"description": "The SilverStripe Framework Installer",
+	"repositories": [
+		{
+			"type": "git",
+			"url": "https://github.com/silverstripe/silverstripe-cms.git"
+		},
+		{
+			"type": "git",
+			"url": "https://github.com/silverstripe/sapphire.git"
+		}
+	],
+	"require": {
+		"php": ">=5.3.2",
+		"silverstripe/cms": "3.0.x-dev",
+		"silverstripe/framework": "3.0.x-dev",
+		"silverstripe-themes/simple": "*"
+	},
+	"minimum-stability": "dev"
+}