Add Word Count to core, to fill a gap

There's a gap in the intermediate exercises, where in Ruby we have exercises that Python doesn't have. So, I promoted a few exercises that are on that same level in Ruby.

Author: emcoding

config.json

@@ -67,6 +67,20 @@
         "type_conversion"
       ]
     },
+    {
+      "slug": "word-count",
+      "uuid": "04316811-0bc3-4377-8ff5-5a300ba41d61",
+      "core": true,
+      "unlocked_by": null,
+      "difficulty": 3,
+      "topics": [
+        "algorithms",
+        "logic",
+        "pattern_recognition",
+        "strings",
+        "text_formatting"
+      ]
+    },
     {
       "slug": "hamming",
       "uuid": "8648fa0c-d85f-471b-a3ae-0f8c05222c89",
@@ -299,20 +313,6 @@
         "type_conversion"
       ]
     },
-    {
-      "slug": "word-count",
-      "uuid": "04316811-0bc3-4377-8ff5-5a300ba41d61",
-      "core": false,
-      "unlocked_by": "high-scores",
-      "difficulty": 3,
-      "topics": [
-        "algorithms",
-        "logic",
-        "pattern_recognition",
-        "strings",
-        "text_formatting"
-      ]
-    },
     {
       "slug": "gigasecond",
       "uuid": "22606e91-57f3-44cf-ab2d-94f6ee6402e8",