title: set current user in context using apollo server
body: <p>i have this middleware and need to get current user to set it in context of apollo server </p>
  
  <pre><code> app.use(async (req, res, next)=&gt;{
   const token = req.headers['authorization'];
   if(token !== "null"){
    try {
        const currentUser = await  jwt.verify(token, process.env.SECRET)
        req.currentUser = currentUser;
    } catch (error) {
        console.log(error);
    }
  
  
   }
   next()
  
     })
  </code></pre>
  
  <p>and need to set current user in context </p>
  
  <pre><code>  const SERVER = new ApolloServer({
        schema,
        context:{
            currentUser //need to set this current user
           }
    })
  
  
     SERVER.applymiddleware({app})
  </code></pre>