Added pairwise bonfire

seed_data/bonfires.json

@@ -483,6 +483,23 @@
       "expect(binaryAgent('01001001 00100000 01101100 01101111 01110110 01100101 00100000 01000110 01110010 01100101 01100101 01000011 01101111 01100100 01100101 01000011 01100001 01101101 01110000 00100001')).to.equal(\"I love FreeCodeCamp!\");"
       ]
   },
+  {
+    "_id" : "a3f503de51cfab748ff001aa",
+    "name": "Pairwise",
+    "difficulty": "2.16",
+    "description": [
+      "Return the sum of all the indexes of elements that can be added to another element of the first array and equal the target provided in the second argument",
+      "For example, pairwise([1,4,2,3,0,5], 5) should return 15 because every element can be paired with another element to equal 5.",
+      "pairwise([1, 3, 2, 4], 4) would only equal 1, because only the first two elements can be paired to equal 4, and the first element has an index of 0!",
+      "Once an element has been used it cannot be reused to pair with another."
+    ],
+    "challengeSeed": "function pairwise(arr, arg) {\n  return arg;\n}\n\npairwise([1,4,2,3,0,5], 5);",
+    "tests": [
+      "expect(pairwise([1,4,2,3,0,5], 5)).to.equal(15);",
+      "expect(pairwise([1, 3, 2, 4], 4])).to.equal(1);",
+      "expect(pairwise([0, 0, 0, 0, 1, 1])).to.equal(10);"
+    ]
+  },
   {
     "_id": "a3f503de51cf954ede28891d",
     "name": "Symmetric Difference",