Unknown Action, The action '1' could not be found for SubjectsController - ruby-on-rails

Question

Mamboo!
Am new to RoR and using Lynda Ruby on Rails 4 Essential Training.
I keep getting " Unknown Action, The action '1' could not be found for SubjectsController" After pressing "Update Subject", on my edit page. I think it can not find update function! What is missing here?
Route.rb
Rails.application.routes.draw do
resources :subjects do get 'index', on: :collection end
match ':controller(/:action(/id))', :via => [:get, :post]
end
subjects_controller.rb
class SubjectsController < ApplicationController
layout false
def index
#subjects = Subject.sorted
end
def show
#subject = Subject.find(params[:id])
end
def new
#subject = Subject.new({:name => "Default"})
end
def create
#subject = Subject.new(subject_params)
if #subject.save
flash[:notice] = "Subject Created Successfully"
redirect_to(:action => 'index')
else
render('new')
end
end
def edit
#subject = Subject.find(params[:id])
end
def update
#subject = Subject.find(params[:id])
if #subject.update_attributes(subject_params)
flash[:notice] = "Subject Updated Successfully"
redirect_to(:action => 'show')
else
render('edit')
end
end
def delete
#subject = Subject.find(params[:id])
end
def destroy
#subject = Subject.find(params[:id])
#subject.destroy
flash[:notice] = "Subject Destroyed Successfully"
redirect_to(:action => "index")
end
private
def subject_params
params.require(:subject).permit(:name, :position, :visible)
end
end
edit.html.erb
<%= link_to("<< Back to List", {:action => 'show'}, :class => 'back-link') %>
<div>
<h2>Update Subjects</h2>
<%= form_for(:subject, :url => {:action => "update", :id => #subject.id}) do |f| %>
<table summary="Subject form field">
<tr>
<th>Name</th>
<td><%= f.text_field(:name) %></td>
</tr>
<tr>
<th>Position</th>
<td><%= f.text_field(:position) %></td>
</tr>
<tr>
<th>Visbile</th>
<td><%= f.text_field(:visible) %></td>
</tr>
</table>
<div class="form-buttons">
<%= f.submit("Update Subject") %>
</div>
<% end %>
</div>
rake routes
$ rake routes
Prefix Verb URI Pattern Controller#Action
sections GET /sections(.:format) sections#index
POST /sections(.:format) sections#create
new_section GET /sections/new(.:format) sections#new
edit_section GET /sections/:id/edit(.:format) sections#edit
section GET /sections/:id(.:format) sections#show
PATCH /sections/:id(.:format) sections#update
PUT /sections/:id(.:format) sections#update
DELETE /sections/:id(.:format) sections#destroy
pages GET /pages(.:format) pages#index
POST /pages(.:format) pages#create
new_page GET /pages/new(.:format) pages#new
edit_page GET /pages/:id/edit(.:format) pages#edit
page GET /pages/:id(.:format) pages#show
PATCH /pages/:id(.:format) pages#update
PUT /pages/:id(.:format) pages#update
DELETE /pages/:id(.:format) pages#destroy
subjects GET /subjects(.:format) subjects#index
POST /subjects(.:format) subjects#create
new_subject GET /subjects/new(.:format) subjects#new
edit_subject GET /subjects/:id/edit(.:format) subjects#edit
subject GET /subjects/:id(.:format) subjects#show
PATCH /subjects/:id(.:format) subjects#update
PUT /subjects/:id(.:format) subjects#update
DELETE /subjects/:id(.:format) subjects#destroy

Answer 1

No need to specify match ':controller(/:action(/id))', :via => [:get, :post] in the routes. resources :subjects will give u route for all new, create, update, show & delete actions. Try this
Rails.application.routes.draw do
resources :subjects
end

Answer 2

As pulkit21 already stated, you don't need that match in your routes. That works for some specific cases, but in general this is usually hacky code that can be avoided with the correct usage of resource routing.
Removing that line in your routes file will then give you the error "No route matches [POST] "/subjects/1". While I don't fully understand why this happens, I do know that the form_for helper don't need to have the :url parameter set. As a matter of fact, when you use the rails scaffold to generate a controller and views, it uses a single form on a partial file for both the new and edit pages. It can do that because it can detect if a object is a new record (don't have an ID yet, so call CREATE) or is an existing record (already has a database ID, so call PUT to update).
In your case, Rails seems to be misunderstanding the :action => "update" part and instead of routing this to the PUT method (which will call the update method on your controller), is routing it to POST.
Try changing your form_for to this:
<%= form_for(#subject) do |f| %>
It's more elegant, readable and simple, and has the advantage of being able to work for both new and edit forms.