migrate to docusaurus (v2) (#266)

Co-authored-by: ibraheemdev <ibrah1440@gmail.com>

src/components/code_block.js

@@ -0,0 +1,27 @@
+import React, { useState, useEffect } from 'react';
+import RenderCodeBlock from '@theme/CodeBlock';
+
+const CodeBlock = ({ example, file, section }) => {
+    const [code, setCode] = useState("");
+
+    useEffect(() => {
+        let isMounted = true; 
+        import(`!!raw-loader!@site/examples/${example}/src/${file || "main.rs"}`)
+            .then(source => {
+                source = source
+                    .default
+                    .match(new RegExp(`\/\/ <${section}>\n([\\s\\S]*)\/\/ <\/${section}>`))[1];
+                if (isMounted) setCode(source)
+            })
+            .catch(err => console.log(err));
+        return () => {
+            isMounted = false;
+        }
+    }, [])
+
+    return (
+        <RenderCodeBlock className="language-rust">{code}</RenderCodeBlock>
+    )
+}
+
+export default CodeBlock;