title: SwiftUI State Variable Not Updating
body: <p>I have a struct User with a list of hobbies as follows:</p>
  
  <pre><code>struct User: Hashable, Codable, Identifiable, Equatable {
      var id: String
      var name: String
      var hobbies: [String]
  }
  </code></pre>
  
  <p>I then generate a list view using a list of users as a state variable. When the button in the list view is clicked a new hobby is added to a user's hobbies.</p>
  
  <pre><code>struct UsersListView: View {
  
      @State var users: [User]
  
  
      var body: some View {
  
                  TitleView(titleText: "Friends")
                      .padding(.leading, 30.0)
  
                  List(userDisplayList) { user in
                       Text(user.name)
                       Text(user.hobbies.joined(separator: ", "))
                       Button(action: {self.users[0].hobbies.append("new hobby")}
                  }
              }
          }
      }
  }
  </code></pre>
  
  <p>However, when I click on the button, the users state variable does not change and remains the same. Can anyone explain what is going on here? </p>