feat: Implement deleteFlow mutation

packages/backend/src/graphql/mutations/delete-flow.ts

@@ -0,0 +1,32 @@
+import { GraphQLString, GraphQLNonNull, GraphQLBoolean } from 'graphql';
+import RequestWithCurrentUser from '../../types/express/request-with-current-user';
+
+type Params = {
+  id: string;
+};
+
+const deleteFlowResolver = async (
+  params: Params,
+  req: RequestWithCurrentUser
+) => {
+  await req.currentUser
+    .$relatedQuery('flows')
+    .delete()
+    .findOne({
+      id: params.id,
+    })
+    .throwIfNotFound();
+
+  return;
+};
+
+const deleteFlow = {
+  type: GraphQLBoolean,
+  args: {
+    id: { type: GraphQLNonNull(GraphQLString) },
+  },
+  resolve: (_: any, params: Params, req: RequestWithCurrentUser) =>
+    deleteFlowResolver(params, req),
+};
+
+export default deleteFlow;