title: How to use graphql type in other files for relationship without duplication
body: <p>I am trying to separate all the tables in different directory. However, I am encountering some problems. Look at the ExpenseItem below. ExpenseType is under ExpenseType directory so graphql throws error. In order to solve that I need to add ExpenseType in ExpeseItem/typeDefs which is redundant. </p>
  
  <p><strong>ExpenseItem/typeDefs</strong></p>
  
  <pre><code>   type ExpenseItem {
          id: ID!
          name: String,
          updatedAt: DateTime,
          expenseType: [ExpenseType]
      }
  </code></pre>
  
  <p>Is there any better way to stitch the schema?</p>
  
  <p>I also tried something like this. However, graphql stop working.
  When I query, it does not goes into the resolver, is there anything wrong on setup?</p>
  
  <pre><code>const schemas = makeExecutableSchema({
    typeDefs: `
      scalar JSON
      scalar DateTime
      type Query {
        test: String
      }
      ${typeDefs1}
      ${typeDefs2}
      ${typeDefs3}
      ${typeDefs4}
  
    `,
    resolvers: {
      // Type resolvers
      JSON: GraphQLJSON,
      DateTime: GraphQLDateTime,
  
      // schema resolvers
      ...resolvers1,
      ...resolvers2,
      ...resolvers3,
      ...resolvers4
    }
  
  })
  
  const server = new ApolloServer({
    schema,
  
    context: { db }
   })
  </code></pre>