Changed hash method again.

lib/crypto.js

@@ -14,7 +14,7 @@ export function hash(...args) {
 }
 
 export function secret() {
-  return hash(process.env.DATABASE_URL, process.env.HASH_SALT);
+  return hash(process.env.HASH_SALT || process.env.DATABASE_URL);
 }
 
 export function salt() {