content: import React from 'react'
  import { Router, Route, IndexRoute, hashHistory } from 'react-router'
  import Home from './home'
  import Main from './main/main'
  import Admin from './admin/admin'
  import Student from './student/student'
  import StudentDashboard from './student/student-dashboard'
  import AdminDashboard from './admin/admin-dashboard'
  import AddConceptForm from './admin/add-concept'
  import AddProblemForm from './admin/add-problem'
  import Assessment from './student/assessment'
  import Report from './student/report'
  
  const App = () => (
    <Router history={hashHistory}>
      <Route path='/' component={Home} />
      <Route path='/main' component={Main}>
        <Route path='/admin' component={Admin} >
          <IndexRoute component = {AdminDashboard} />
          <Route path='/concept-form' component={AddConceptForm} />
          <Route path='/problem-form' component={AddProblemForm} />
        </Route>
        <Route path='/student' component={Student}>
          <IndexRoute component={StudentDashboard} />
          <Route path='/assessment' component={Assessment} />
          <Route path='/report' component={Report} />
        </Route>
      </Route>
    </Router>
  )
  
  export default App
  