Thanks to a follower's suggestion, from now onwards i will use #bilaltutorials tag for my articles.

Adding images to rails app

The Task

Add image field to posts and save those images for later use

Preparing for it

• 1- install image magik

sudo apt-get -y install imagemagick gsfonts

check to see if it is installed

which convert

typing above command should return the following output

• 2- add paperclip gem in gemfile

gem "paperclip", "~> 6.0.0"

and do bundle install

• 3- create migration

rails generate paperclip post cover_photo

• 4- rake db:migrate

• 5- open Post model and add following

  has_attached_file :cover_photo, styles: {large: "600x600>", medium: "300x300>", thumb: "100x100>" }, default_url: "/images/:style/missing.png"
  validates_attachment_content_type :cover_photo, content_type: /\Aimage\/.*\z/

• 6- update environment variables to use image magik
  in config/environments/development.rb

Paperclip.options[:command_path] = "/usr/local/bin/"

• 7- Edit forms

<%= form_for @post, url: posts_path, html: { multipart: true } do |form| %>
  <%= form.file_field :cover_photo %>
  <%= form.submit %>
<% end %>

• 8- Permit controller to accept new form field

params.require(:post).permit(:title,:cover_photo,:content)

That's all you need to do :) and voila you have images added to your posts.