Add missing doc entries to the docs/config.md (#334)

Author: IsaacG

docs/config.json

@@ -1,12 +1,33 @@
 {
   "docs": [
+    {
+      "uuid": "6691fcad-1ab4-470d-89d8-8c17b2cd508c",
+      "slug": "about",
+      "path": "docs/ABOUT.md",
+      "title": "About Objective-C",
+      "blurb": "Learn about the Objective-C language"
+    },
     {
       "uuid": "014402ed-4b07-4659-b007-55df6f834bc6",
       "slug": "installation",
       "path": "docs/INSTALLATION.md",
       "title": "Installing Objective-C locally",
       "blurb": "Learn how to install Objective-C locally to solve Exercism's exercises on your own machine"
     },
+    {
+      "uuid": "f321b5d1-8521-4e7c-956f-29d9a3d895f5",
+      "slug": "learning",
+      "path": "docs/LEARNING.md",
+      "title": "Learn Objective-C",
+      "blurb": "Start here to learn how to use Objective-C"
+    },
+    {
+      "uuid": "ffa3710b-5def-4db5-80ec-07560fef32c1",
+      "slug": "resources",
+      "path": "docs/RESOURCES.md",
+      "title": "Objective-C Resources",
+      "blurb": "Some useful references to use when writing Objective-C"
+    },
     {
       "uuid": "1ae7054b-ad70-4ceb-9fa1-84978a4171f4",
       "slug": "tests",