feat: Add a link to the dev matrix channel

Make it easier to onboard new devs

README.md

@@ -2,7 +2,9 @@
   <img height="300" src="./logos/1500x1500.png" alt="10101 Logo">
 </p>
 
-# 10101 (*Ten-Ten-One*) - Decentralised finance. For real.
+# 10101 (_Ten-Ten-One_) - Decentralised finance. For real.
+
+<img href="https://matrix.to/#/#tentenone:matrix.org" alt="10101 dev chat" src="https://img.shields.io/matrix/tentenone%3Amatrix.org">
 
 10101 combines the power of a self-custodial on-chain and off-chain wallet with the vast world of trading. 10101 - a numeral palindrome and the binary representation of 21 - as in 21 million possible bitcoin. The vision of 10101 embodies what Bitcoin stands for: Decentralized and censorship resistant money.