add Readme

src/chains/README.md

@@ -0,0 +1,25 @@
+# Directory Layout
+
+**We accept all blockchains which have 10+ independent validators.**
+
+- Submit configs for mainnet, go to https://github.com/ping-pub/explorer/tree/master/src/chains/mainnet
+
+- Submit configs for testnet, go to https://github.com/ping-pub/explorer/tree/testnet/src/chains/testnet
+
+# Sample of Config
+
+```json
+{
+    "chain_name": "cosmos",
+    "coingecko": "cosmos", 
+    "api":"https://cosmos.api.ping.pub", 
+    "sdk_version": "0.42.6",
+    "addr_prefix": "cosmos",
+    "logo": "https://dl.airtable.com/.attachments/e54f814bba8c0f9af8a3056020210de0/2d1155fb/cosmos-hub.svg"
+}
+```
+- **chain_name** the name to identify the chain on ping.pub
+- **coingecko**  the id of the token on chain. if there multi-tokens, using `["tokenA","tokenB"]
+- **api** the rest api endpoint. make sure CORS is enabled: `Allow-Control-Allow-Origin: *`
+
+