Update README.md

README.md

@@ -23,7 +23,22 @@ Cryptographic javascript-functions for ethereum and tutorials on how to use them
 
   In this tutorial we will use the ethereum-identites and asymmetric cryptography to send an encrypted and signed message from Alice to Bob.
 
-## Functions
+## Sponsored by
+
+<p align="center">
+    <a href="https://rxdb.info/?utm_source=github&utm_medium=repo&utm_campaign=github-eth-crypto-readme">
+        <img
+            src="https://github.com/pubkey/rxdb/raw/master/docs-src/files/logo/logo_text.svg"
+            alt="Sponsored by RxDB"
+            width="300"
+         />
+         <br />
+         <br />
+         <span>The <b>JavaScript Database</b></span>
+    </a>
+</p>
+
+## Using eth-crypto
 
 ### Install