Get off off rails-assets

Just moving the things we currently use (and should drop in the ASAP) to vendor/assets

vendor/assets/javascripts/holderjs/src/meteor/package.js

@@ -0,0 +1,12 @@
+Package.describe({
+    summary: '%summary%',
+    version: '%version%',
+    name: 'imsky:holder',
+    git: 'https://github.com/imsky/holder',
+});
+
+Package.onUse(function(api) {
+    api.versionsFrom('0.9.0');
+    api.export('Holder', 'client');
+    api.addFiles('holder.js', 'client');
+});

vendor/assets/javascripts/holderjs/src/meteor/shim.js

@@ -0,0 +1,5 @@
+(function(ctx, isMeteorPackage) {
+    if (isMeteorPackage) {
+        Holder = ctx.Holder;
+    }
+})(this, typeof Meteor !== 'undefined' && typeof Package !== 'undefined');