Rename a Database column using Rails migration

You need to create a separate migration to do this.

rails g migration FixColumnName

class FixColumnName < ActiveRecord::Migration
  def change
    rename_column :table_name, :old_column, :new_column
  end
end

---

If you happen to have a whole bunch of columns to rename, or something that would have required repeating the table name over and over again.

rename_column :table_name, :old_column1, :new_column1
rename_column :table_name, :old_column2, :new_column2
...

You could use change_table to keep things a little neater.

class FixColumnNames < ActiveRecord::Migration
  def change
    change_table :table_name do |t|
      t.rename :old_column1, :new_column1
      t.rename :old_column2, :new_column2
      ...
    end
  end
end

Understanding attr_accessible – Secure Your Rails Application

What is the attr_accessible directive ?

So, when you open up your devise User model, and you notice a line similar to that :

attr_accessible :username, :email, :password

The first thing that is important to know about, if you don’t really, is that attr_accessible is simply an instance method, a function as most non-ruby programmers would name. This is actually a part of ActiveModel::MassAssignmentSecurity::ClassMethods, which already some something about its usage. It’s there to prevent mass assignment security attacks.
But what exactly is that ?

 In Ruby on Rails, a mass assignment is when you save more than one attributes of a model to your database. For instance :

current_user.save current_user.update_attributes(...) current_user.update_attribute(...)   <- THIS IS NOT A MASS ASSIGNMENT

Changes to be made after you Change your Repository URL

Change
repository URL





You
simply need to remove the origin remote that has the incorrect
reference with:

$
git remote rm origin

Then
restart the add, and push, and you should be good to go.

$
git remote add origin git@github.com:nikhil/example.git 

$
git push -u origin master




Capistrano
deploy fails after the repository URL changes - How to fix?





You
need to run following command before you start deploying with your
new URL.

cap
deploy:cleanup -s keep_releases=0



Apparently
you will also need to remove shared/cached-copy, because this doesn't
cleaned by the capistrano call above.

What's new in Ruby on Rails 4 - Part_1

Cheers,