Default .env: add instructions on how to get an API key (liquity#749)

INSTRUCTIONS.md

@@ -41,7 +41,7 @@ cd frontend/app
 cp .env .env.local
 ```
 
-Edit the newly created `.env.local` to set the app [environment variables](./frontend/app/README.md#environment).
+Edit the newly created `.env.local` to set the app [environment variables](./frontend/app/README.md#environment). The `NEXT_PUBLIC_SUBGRAPH_URL` need to be set manually. You might want to create a [GraphSeer](https://beta.graphseer.com/) account to get an API key.
 
 Optional: you can generate a set of contract addresses for the `.env.local` file by running the following command:
 

frontend/app/.env

@@ -27,7 +27,14 @@ NEXT_PUBLIC_DELEGATE_AUTO=0x0000000000000000000000000000000000000000
 NEXT_PUBLIC_KNOWN_INITIATIVES_URL=https://api.liquity.org/v2/known-initiatives/mainnet.json
 NEXT_PUBLIC_LIQUITY_STATS_URL=https://api.liquity.org/v2/mainnet.json
 NEXT_PUBLIC_SAFE_API_URL=https://safe-transaction-mainnet.safe.global/api
-NEXT_PUBLIC_SUBGRAPH_URL=https://gateway.thegraph.com/api/f7317a79b9fe8215d184d5c82e5aac8e/subgraphs/id/J2f756n9odYccBcntvSRia72Nn3gWcY4HQNfvU9WvJP3
+
+# Uncomment one of these:
+#
+# Create an account on https://beta.graphseer.com/ and insert your API key:
+# NEXT_PUBLIC_SUBGRAPH_URL=https://graph-gateway.graphops.xyz/api/{graphseer_api_key}/subgraphs/id/J2f756n9odYccBcntvSRia72Nn3gWcY4HQNfvU9WvJP3
+#
+# Or use a subgraph API key:
+# NEXT_PUBLIC_SUBGRAPH_URL=https://gateway.thegraph.com/api/{subgraph_api_key}/subgraphs/id/J2f756n9odYccBcntvSRia72Nn3gWcY4HQNfvU9WvJP3
 
 NEXT_PUBLIC_COLL_0_TOKEN_ID=ETH
 NEXT_PUBLIC_COLL_1_TOKEN_ID=WSTETH