Tweaked gitignore

gitignore removed all composer and npm files, so automated builds would fail

conf/site/node_modules/collect.js/docs/api/diff.md

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+# `diff()`
+
+The diff method compares the collection against another collection or a plain array based on its values. This method will return the values in the original collection that are not present in the given collection:
+
+```js
+const collection = collect([1, 2, 3, 4, 5]);
+
+const diff = collection.diff([1, 2, 3, 9]);
+
+diff.all();
+
+// [4, 5]
+```
+
+[View source on GitHub](https://github.com/ecrmnn/collect.js/blob/master/src/methods/diff.js)