I wanted my new project with rails 4. So, i started with rails with following 

tasks in mind.

1. responsive using bootstrap/foundation 

2. user authentication.
3. debugging

To make this task achievable there are following gem in rails.

1.devise/omniauth - for othentication
2.bootstrap-sass - for bootstrap 
3.rails_layout - for layout generation

Here is the process include these in your Gemfile.
Note 

gem 'rails_layout' , group: :development,

1.1 for the devise follow the following points here.
https://github.com/plataformatec/devise#getting-started

2.2 Now we have added the bootstrap in our project now, we need to generate the layout using bootstrap or foundation or Zurb.
https://github.com/plataformatec/devise#getting-started
follow the commands.

The “layout:install” Command
The command will rename application.css to application.css.scss.
It will add:
  • framework_and_overrides.css.scss

3. For Debugging]

group :development do 

  gem 'better_errors'
  gem 'binding_of_caller'
  gem 'pry_rails'
  gem 'meta_request'

end

4.  list of helpful gems 

  1. paperclip
  2. rmagic
  3. aws-sdk
  4. annotate
  5. roo #for csv, EXLE files
  6. pdfkit #for the pdf creation 
  7. suspot # for full text search
  8. jazz_hands # For perfect de-bugging 
  9. nakogiri #for pagination 
  10. sunspot
  11. quite_assets
For more visit this link links to gems blog

For  the file upload on the S3 bucket.
https://devcenter.heroku.com/articles/paperclip-s3 

Some rails TIPS man.

1. include?
This is used to check for the word in the string.
"Hello".include? "l" => true

2. repond_to ?
This will be true if the var. will have the function to work with.

3. "hello".methods

4. "Hello".gsub!(/l/,"x");

5. in Rails to avoid SQL Injection 
 @tasks = Task.find(:all, :conditions => ["name LIKE ?", "%#{params[:query]}%"])


6. For the enum in the models to work.


7. Keywords for the ruby
  • break
  • next
  • redo
  • retry
  • is_a? /kind_of?
  • instance_of?
  • kind_of?
  • defined?
  • to_s
  • to_sym / to_intern --to_s
  • upto -- downto  88.upto(90){ }
  • collect / collect!


0down vote
As Chris said, you'll want to use a third party service like S3 and if you do end up using Paperclip then you'll eventually have something like this example in your model.
has_attached_file :photo,
        :styles => { :thumb=> "100x100", :small  => "300x300" },
        :storage => :s3,
        :s3_credentials => "#{Rails.root.to_s}/config/s3.yml",
        :path => "/:id/:style/:filename"
And in your config directory you'll have an s3.yml credentials file that would look like:
development:
   bucket: blahblah
   access_key_id: sfoi40j8elkfv08hwo
   secret_access_key: DJyWuRtsfoi40j8elkfv08hwos0m8qt

production:
   bucket: blahblah
   access_key_id: sfoi40j8elkfv08hwo
   secret_access_key: DJyWusfoi40j8elkfv08hwos0m8


qt



8. For the the nested resources the views.
http://stackoverflow.com/questions/16999292/examples-of-new-create-actions-for-has-many-through-associations-nested

9. Eager loading for the rails if this is needed. 

10.