web3.eth.accounts[0] returns undefined and app.vote(1,{ from:web3.eth.accounts[0] }) is giving error about election HOT 2 OPEN

Did you solve the problems?
I have this one:
truffle(development)> app.vote(1, {from:accounts[2]})
evalmachine.:0
app.vote(1, {from:accounts[0]})
^

Uncaught ReferenceError: app is not defined
at evalmachine.:0:1
at sigintHandlersWrap (vm.js:272:15)
at Script.runInContext (vm.js:127:14)
at runScript (C:\Users\Eirini\AppData\Roaming\npm\node_modules\truffle\build\webpack:\packages\core\lib\console.js:227:1)
at Console.interpret (C:\Users\Eirini\AppData\Roaming\npm\node_modules\truffle\build\webpack:\packages\core\lib\console.js:242:1)
at ReplManager.interpret (C:\Users\Eirini\AppData\Roaming\npm\node_modules\truffle\build\webpack:\packages\core\lib\repl.js:129:1)
at bound (domain.js:427:14)
at REPLServer.runBound [as eval] (domain.js:440:12)
at REPLServer.onLine (repl.js:760:10)
at REPLServer.emit (events.js:315:20)

from election.

i fixed it!

from election.