# Uninitialized constant - Please Help Me

**URL:** <https://www.ruby-forum.com/t/uninitialized-constant-please-help-me/188245>\
**Category:** Rails\
**Created:** [May 8, 2010, 10:57am UTC](https://www.ruby-forum.com/t/uninitialized-constant-please-help-me/188245 "2010-05-08T10:57:02Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![craigrails](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/c2a13f/32.png) [@craigrails](https://www.ruby-forum.com/u/craigrails)\
**Post date:** [May 8, 2010, 10:57am UTC](https://www.ruby-forum.com/t/uninitialized-constant-please-help-me/188245/1 "2010-05-08T10:57:02Z")

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Hello everyone,

I’ve decided to take the step into creating a mini-forum for my  
website where users can open new posts on exixting topics and allow  
people to discuss things etc…

I am following a tutorial in the book: APRESS - Practical Rails Social  
Networking Sites and have hit a minor issue.

Part of the Forum requirements is to add a moderator role to allow  
only certain individuals the ability to manage topics etc.

That code is in the moderator\_role.rb migration file which looks like  
this:

class AddModeratorRole \< ActiveRecord::Migration  
def self.up  
moderator\_role = Role.create(:name =\> ‘Moderator’)  
admin\_user = User.find\_by\_username(‘Admin’)  
admin\_user.roles \<\< moderator\_role  
end  
def self.down  
moderator\_role = Role.find\_by\_name(‘Moderator’)  
admin\_user = User.find\_by\_username(‘Admin’)  
admin\_user.roles.delete(moderator\_role)  
moderator\_role.destroy  
end  
end

WHen i run rake db:migrate I get the following error:

# == AddModeratorRole: migrating

rake aborted!  
An error has occurred, all later migrations canceled:

uninitialized constant AddModeratorRole::Role

I’m not too sure what’s wrong as I’ve followed the book so far to the  
word.

ANy ideas, help on how to resolve this would be really appreciated.

Many Thanks

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<div class="post-metadata">

**Author:** ![craigrails](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/c2a13f/32.png) [@craigrails](https://www.ruby-forum.com/u/craigrails)\
**Post date:** [May 8, 2010, 12:48pm UTC](https://www.ruby-forum.com/t/uninitialized-constant-please-help-me/188245/2 "2010-05-08T12:48:49Z")

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On 8 May 2010 09:55, RubyonRails\_newbie [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
wrote:

> # only certain individuals the ability to manage topics etc. def self.down == AddModeratorRole: migrating
> 
> rake aborted!  
> An error has occurred, all later migrations canceled:
> 
> uninitialized constant AddModeratorRole::Role

Have you accidentally missed out a step that creates the roles table?

Colin

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<div class="post-metadata">

**Author:** ![craigrails](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/c2a13f/32.png) [@craigrails](https://www.ruby-forum.com/u/craigrails)\
**Post date:** [May 8, 2010, 6:10pm UTC](https://www.ruby-forum.com/t/uninitialized-constant-please-help-me/188245/3 "2010-05-08T18:10:40Z")

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Thanks for the reply COlin, Yes i’d missed that. All sorted now.

Thanks for that!