Sinatra login/logout

actions.rb

# Homepage (Root path)
enable :sessions

helpers do
    def current_user
      begin
          @current_user = User.find(session["user_id"].to_i)
          # @current_user = User.find(response.cookies["user_id"].to_i)
      rescue
          @current_user = nil
      end
    end
end

get '/' do
  erb :index
end

get '/login' do
  erb :login
end

post '/login' do
  users = User.where(email: params[:username], password: params[:password])
  if users.length == 1
    user = users.first
    # response.set_cookie("user_id", value: user.id, expires: Time.now + 60*60*24*365 )
    session["user_id"] = user.id
    redirect '/'
  else
    @error = true
    erb :login
  end
end

get '/signup' do
  erb :signup
end

post '/signup' do
  user = User.new(email: params[:username], password: params[:password])
  user.save

  redirect '/login'
end

get '/logout' do
  session.clear
  # response.set_cookie("user_id", value: "", expires: Time.now - 100 )
  redirect '/'
end

get '/messages' do
  @messages = Message.all
  erb :'messages/index'
end

get '/messages/new' do
  @message = Message.new
  erb :'messages/new'
end

get '/messages/:id' do
  @message = Message.find params[:id]
  erb :'messages/show'
end

post '/comments' do
    message_id = params[:message_id]
end
post '/messages/:id/comments' do
end

post '/messages' do
  @message = Message.new(
    title:   params[:title],
    content: params[:content],
    author:  params[:author]
  )
  if @message.save
    redirect '/messages'
  else
    erb :'messages/new'
  end
end

login.erb

<h1>Login</h1>

<% if @error %>
    <div class="error">Login failed.</div>
<% end %>

<form action="/login" method="post">

    <input type="text" name="username" placeholder="Username" />
    <input type="password" name="password" placeholder="Password" />

    <input type="submit" name="button" value="Login" />

</form>