old_contents: import * as ActionTypes from '../actions/ActionTypes'
  
  function UserReducer(state = [], action) {
    switch (action.type) {
      case ActionTypes.CREATE_USER_SUCCESS:
        return [
          ...state,
          Object.assign({}, action.user),
        ]
    default:
      return state
    }
  }
  
  export default UserReducer
  
new_contents: import * as ActionTypes from '../actions/ActionTypes'
  
  function UserReducer(state = {}, action) {
    switch (action.type) {
      case ActionTypes.CREATE_USER_SUCCESS:
        return {
          ...state,
          ...action.user,
        }
    default:
      return state
    }
  }
  
  export default UserReducer
  
subject: Store single user instead of array