feat(challenge-md): Parse solutions from md

tools/challenge-md-parser/solution-to-data.js

@@ -0,0 +1,20 @@
+const visit = require('unist-util-visit');
+const { selectAll } = require('hast-util-select');
+
+const { sectionFilter } = require('./utils');
+
+function createPlugin() {
+  return function transformer(tree, file) {
+    function visitor(node) {
+      if (sectionFilter(node, 'solution')) {
+        const solutions = selectAll('code', node).map(
+          element => element.children[0].value
+        );
+        file.data.solutions = solutions;
+      }
+    }
+    visit(tree, 'element', visitor);
+  };
+}
+
+module.exports = createPlugin;