MongoMapper now not overrides database name in MONGOHQ_URL configuration if provided. It also works on Heroku.

.gitignore

@@ -1,22 +1,21 @@
 .bundle
+.DS_Store
 .idea
+.rvmrc
 *.swap
-*.swp
 *.swo
+*.swp
 *~
-.bundle
+bin/*
+config/app_config.yml
+config/fb_config.yml
+config/initializers/secret_token.rb
 db/*.sqlite3
 log/*
-tmp/**/*
+nbproject
 gpg/diaspora-development/*.gpg
 gpg/diaspora-production/*.gpg
 gpg/*/random_seed
 public/uploads/*
-.rvmrc
-.DS_Store
-config/app_config.yml
-bin/*
-nbproject
-config/initializers/secret_token.rb
 public/source.tar
-config/fb_config.yml
+tmp/**/*

config/initializers/_mongo.rb

@@ -2,13 +2,10 @@
 #   licensed under the Affero General Public License version 3.  See
 #   the COPYRIGHT file.
 
-if ENV['MONGOHQ_URL']
+ENV['MONGODB_URL'] = ENV['MONGOHQ_URL'] || URI::Generic.build(:scheme => 'mongodb', :host => APP_CONFIG['mongo_host'], :port => APP_CONFIG['mongo_port'], :path => "/diaspora-#{Rails.env}").to_s
-  MongoMapper.config = {RAILS_ENV => {'uri' => ENV['MONGOHQ_URL']}}
-else
-  MongoMapper.connection = Mongo::Connection.new(APP_CONFIG['mongo_host'], APP_CONFIG['mongo_port'])
-end
 
-MongoMapper.database = "diaspora-#{Rails.env}"
+MongoMapper.config = {RAILS_ENV => {'uri' => ENV['MONGODB_URL']}}
+MongoMapper.connect RAILS_ENV
 
 if defined?(PhusionPassenger)
    PhusionPassenger.on_event(:starting_worker_process) do |forked|
@@ -16,4 +13,4 @@ if defined?(PhusionPassenger)
    end
 end
 
-Magent.connection  = Mongo::Connection.new(APP_CONFIG['mongo_host'], APP_CONFIG['mongo_port'])
+Magent.connection = MongoMapper.connection