add merge method for collections and arrays

dist/classes/collection/Collection.js

@@ -286,6 +286,26 @@ var Collection = function () {
       return this.sum(key) / this.items.length;
     }
 
+    // Get the average of all values, or all values of a given column
+
+  }, {
+    key: 'merge',
+    value: function merge(items) {
+      var _this2 = this;
+
+      if (items instanceof Collection) {
+        items.each(function (item, key) {
+          _this2.add(item);
+        });
+      } else {
+        items.forEach(function (item) {
+          _this2.add(item);
+        });
+      }
+
+      return this;
+    }
+
     // PRIVATE METHODS
     // Private: used to determine if an item should be added to list based on where query
 

src/classes/collection/Collection.js

@@ -211,6 +211,21 @@ class Collection {
       return this.sum(key) / this.items.length
     }
 
+    // Get the average of all values, or all values of a given column
+    merge(items) {
+      if(items instanceof Collection) {
+        items.each((item, key) => {
+          this.add(item)
+        })
+      } else {
+        items.forEach((item) => {
+          this.add(item)
+        })
+      }
+
+      return this
+    }
+
     // PRIVATE METHODS
     // Private: used to determine if an item should be added to list based on where query
     _passesWhereQuery(item) {

test/collection.js

@@ -442,6 +442,29 @@ describe('#Collection', function() {
 
         expect(collection.average('count')).to.equal(2.5)   
     })
+
+    it('it should be able to merge another collection', function() {
+        let items1 = [1, 1, 2, 4]
+        let collection1 = new Collection(items1)
+
+        let items2 = [99, 100]
+        let collection2 = new Collection(items2)  
+
+        let collection = collection1.merge(collection2)
+
+        expect(collection.count()).to.equal(6)
+    })
+
+    it('it should be able to merge an array into the collection', function() {
+        let items1 = [1, 1, 2, 4]
+        let collection1 = new Collection(items1)
+
+        let items2 = [99, 100]
+
+        let collection = collection1.merge(items2)
+
+        expect(collection.count()).to.equal(6)
+    })
 
 });