Sinatra, Mongoid ActiveRecord::AdapterNotSpecified: database configuration does not specify adapter - ruby

Question

I am trying to create a create_indexes rake task for creating indexes for MongoDb records in my application.
I have Rakefile in the top directory of my application, with the following code.
require "./app"
set :database_file, "./config/mongoid.yml"
Dir.glob('lib/tasks/*.rake').each { |r| load r}
I have create a db.rake file in the lib/tasks folder in my app
namespace :db do
task :create_indexes => :environment do
#
begin
Rails.application.eager_load!
rescue Object => e
end
#
begin
Bundler.require(:default, :assets, 'production')
rescue Object => e
end
#
to_index_models = []
ObjectSpace.each_object(Module) do |object|
begin
to_index_models.push(object) if object.respond_to?(:create_indexes)
rescue Object => e
warn "failed on: #{ object }.respond_to?(:create_indexes)"
end
end
#
to_index_models.sort! do |a, b|
begin
a.name <=> b.name
rescue Object
0
end
end
#
begin
to_index_models.uniq!
rescue Object
end
#
to_index_models.each do |model|
begin
model.create_indexes
puts "indexed: #{ model }"
rescue Object => e
warn "failed on: #{ model }#create_indexes"
end
end
end
end
This was taken from http://grokbase.com/t/gg/mongoid/12akaq1na7/equivalent-of-create-indexes-rake-task-in-non-rails-environment#20121106gzwpoiifznpdxa3ugtzdvjgplq
And my mongoid.yml file is a basic connection to localhost file:
development:
sessions:
default:
database: mongoid
hosts:
- localhost:27017
But whenever I am trying to run the rake task as:
rake db:create_indexes[development]
I am getting the following error:
rake aborted!
ActiveRecord::AdapterNotSpecified: database configuration does not specify adapter
/Users/harshsingh/.rvm/gems/ruby-2.1.2/gems/activerecord-4.2. 0/lib/active_record/connection_adapters/connection_specification.rb:171:in `spec'
/Users/harshsingh/.rvm/gems/ruby-2.1.2/gems/activerecord-4.2.0/lib/active_record/connection_handling.rb:50:in `establish_connection'
/Users/harshsingh/.rvm/gems/ruby-2.1.2/gems/sinatra-activerecord-2.0.4/lib/sinatra/activerecord.rb:39:in `database='
/Users/harshsingh/.rvm/gems/ruby-2.1.2/gems/sinatra-1.4.5/lib/sinatra/base.rb:1208:in `set'
/Users/harshsingh/.rvm/gems/ruby-2.1.2/gems/sinatra-activerecord-2.0.4/lib/sinatra/activerecord.rb:33:in `database_file='
/Users/harshsingh/.rvm/gems/ruby-2.1.2/gems/sinatra-1.4.5/lib/sinatra/base.rb:1208:in `set'
/Users/harshsingh/.rvm/gems/ruby-2.1.2/gems/sinatra-1.4.5/lib/sinatra/base.rb:1982:in `block (2 levels) in delegate'
/Users/harshsingh/Documents/Codes/mogreet-requestbin/Rakefile:2:in `<top (required)>'
/Users/harshsingh/.rvm/gems/ruby-2.1.2/bin/ruby_executable_hooks:15:in `eval'
/Users/harshsingh/.rvm/gems/ruby-2.1.2/bin/ruby_executable_hooks:15:in `<main>'
(See full trace by running task with --trace)