In progress sign in changes.

client/src/graphql/resolvers.js

@@ -0,0 +1,26 @@
+import { gql } from "apollo-boost";
+
+export const typeDefs = gql`
+  extend type Mutation {
+    SetCurrentUser(user: User!): User!
+  }
+`;
+
+const GET_CURRENT_USER = gql`
+  {
+    currentUser @client
+  }
+`;
+
+export const resolvers = {
+  Mutation: {
+    setCurrentUser: (_root, { user }, { cache }) => {
+      cache.writeQuery({
+        query: GET_CURRENT_USER,
+        data: { currentUser: user }
+      });
+
+      return user;
+    }
+  }
+};