[website] Add slack invite on home page (#903)

Author: MehulBatra

website/src/pages/index.module.css

@@ -49,3 +49,22 @@
   justify-content: center;
 }
 
+.join_slack_button {
+  margin-left: 20px;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+}
+
+.github_button {
+  margin-left: 20px;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+}
+
+.buttonIcon {
+  margin-right: 8px;
+  width: 20px;
+  height: 20px;
+}

website/src/pages/index.tsx

@@ -41,10 +41,26 @@ function HomepageHeader() {
           </Link>
 
           <Link
-            className="source_code_button button button--secondary button--lg"
-            to="https://github.com/alibaba/fluss">
+              className={clsx("button button--secondary button--lg", styles.github_button)}
+              to="https://github.com/alibaba/fluss">
+            <img
+                src="img/github_icon.svg"
+                alt="GitHub"
+                className={styles.buttonIcon}
+            />
             GitHub
           </Link>
+
+          <Link
+              className={clsx("button button--secondary button--lg", styles.join_slack_button)}
+              to="https://join.slack.com/t/fluss-hq/shared_invite/zt-33wlna581-QAooAiCmnYboJS8D_JUcYw">
+            <img
+                src="img/slack_icon.svg"
+                alt="Slack"
+                className={styles.buttonIcon}
+            />
+            Slack
+          </Link>
         </div>
       </div>
     </header>