Trying to "redirect_to :back" after logging in

I'm trying to redirect to the previous page after a user logs in. I am using a bootstrap modal for login/register forms but if someone doesn't have JS enabled on their browser and are taken to the '/login' page, I want to make sure they are redirected to the root url. I know current_page? does not work with POST requests.

I've tried tons of things so the following code is redirecting correctly from the '/login' page to the root url but I am not being redirected to ':back' when logging in using the bootstrap modal.

This is from SessionsController: (PS- I have sessions#new/sessions#create as /login in routes)

def create
    user = User.find_by(email: params[:email]) 
    if user && user.authenticate(params[:password])
        session[:user_id] = user.id

            if request.path === '/login'
                redirect_to '/'
            else
                redirect_to :back
            end

            flash[:success] = "Logged in."

    else
        flash.now[:danger] = "Email and password did not match. Please try again."
        render :new
    end
end

def destroy
    session[:user_id] = nil
    flash[:success] = "Logged out."
    redirect_to '/'
end

Routes.rb:

Rails.application.routes.draw do

root to: 'home#home'

resources :users

get '/login', to: 'sessions#new'
post '/login', to: 'sessions#create'
get '/logout', to: 'sessions#destroy'

end