fix: fix contract queries

packages/db/lib/db.dart

@@ -401,15 +401,18 @@ class Database {
     return queryMany(allContractsQuery(), contractFromColumnMap);
   }
 
+  /// Get a contract by id.
   Future<Contract?> contractById(String id) async {
     final query = contractByIdQuery(id);
     return queryOne(query, contractFromColumnMap);
   }
 
+  /// Get all contracts which are !accepted.
   Future<Iterable<Contract>> unacceptedContracts() async {
     return queryMany(unacceptedContractsQuery(), contractFromColumnMap);
   }
 
+  /// Get all contracts which are !fullfilled and !expired.
   Future<Iterable<Contract>> activeContracts() async {
     return queryMany(activeContractsQuery(), contractFromColumnMap);
   }

packages/db/lib/src/contract.dart

@@ -25,15 +25,18 @@ Query contractByIdQuery(String id) {
   );
 }
 
+/// Get all contracts which are !fulfilled and expiration date is in the future.
 Query activeContractsQuery() {
-  return const Query(
-    "SELECT * FROM contract_ WHERE json->>'status' = 'active'",
+  return Query(
+    "SELECT * FROM contract_ WHERE json->>'fulfilled' = 'false' AND json->>'expiration' > @now",
+    parameters: {'now': DateTime.timestamp()},
   );
 }
 
+/// Get all contracts which are !accepted.
 Query unacceptedContractsQuery() {
   return const Query(
-    "SELECT * FROM contract_ WHERE json->>'status' = 'unaccepted'",
+    "SELECT * FROM contract_ WHERE json->>'accepted' = 'false'",
   );
 }