Mongoid fails on Heroku

gistfile1.txt

irb(main):013:0> Shop.count
NoMethodError: undefined method `[]' for nil:NilClass
	from /app/vendor/bundle/ruby/1.9.1/gems/moped-1.1.5/lib/moped/node.rb:74:in `block in command'
	from /app/vendor/bundle/ruby/1.9.1/gems/moped-1.1.5/lib/moped/node.rb:522:in `[]'
	from /app/vendor/bundle/ruby/1.9.1/gems/moped-1.1.5/lib/moped/node.rb:522:in `block (3 levels) in flush'
	from /app/vendor/bundle/ruby/1.9.1/gems/moped-1.1.5/lib/moped/node.rb:521:in `map'
	from /app/vendor/bundle/ruby/1.9.1/gems/moped-1.1.5/lib/moped/node.rb:521:in `block (2 levels) in flush'
	from /app/vendor/bundle/ruby/1.9.1/gems/moped-1.1.5/lib/moped/node.rb:113:in `ensure_connected'
	from /app/vendor/bundle/ruby/1.9.1/gems/moped-1.1.5/lib/moped/node.rb:517:in `block in flush'
	from /app/vendor/bundle/ruby/1.9.1/gems/moped-1.1.5/lib/moped/node.rb:532:in `logging'
	from /app/vendor/bundle/ruby/1.9.1/gems/moped-1.1.5/lib/moped/node.rb:516:in `flush'
	from /app/vendor/bundle/ruby/1.9.1/gems/moped-1.1.5/lib/moped/node.rb:505:in `process'
	from /app/vendor/bundle/ruby/1.9.1/gems/moped-1.1.5/lib/moped/node.rb:70:in `command'
	from /app/vendor/bundle/ruby/1.9.1/gems/moped-1.1.5/lib/moped/node.rb:356:in `refresh'
	from /app/vendor/bundle/ruby/1.9.1/gems/moped-1.1.5/lib/moped/cluster.rb:101:in `block in refresh'
	from /app/vendor/bundle/ruby/1.9.1/gems/moped-1.1.5/lib/moped/cluster.rb:114:in `each'
	from /app/vendor/bundle/ruby/1.9.1/gems/moped-1.1.5/lib/moped/cluster.rb:114:in `refresh'
	from /app/vendor/bundle/ruby/1.9.1/gems/moped-1.1.5/lib/moped/cluster.rb:67:in `nodes'
	from /app/vendor/bundle/ruby/1.9.1/gems/moped-1.1.5/lib/moped/cluster.rb:136:in `with_primary'
	from /app/vendor/bundle/ruby/1.9.1/gems/moped-1.1.5/lib/moped/session/context.rb:108:in `with_node'
	from /app/vendor/bundle/ruby/1.9.1/gems/moped-1.1.5/lib/moped/session/context.rb:50:in `command'
	from /app/vendor/bundle/ruby/1.9.1/gems/moped-1.1.5/lib/moped/database.rb:76:in `command'
	from /app/vendor/bundle/ruby/1.9.1/gems/moped-1.1.5/lib/moped/query.rb:36:in `count'
	from /app/vendor/bundle/ruby/1.9.1/gems/mongoid-3.0.1/lib/mongoid/contextual/mongo.rb:68:in `count'
	from /app/vendor/bundle/ruby/1.9.1/gems/mongoid-3.0.1/lib/mongoid/contextual.rb:18:in `count'
	from /app/vendor/bundle/ruby/1.9.1/gems/mongoid-3.0.1/lib/mongoid/finders.rb:22:in `count'
	from (irb):18
	from /app/vendor/bundle/ruby/1.9.1/gems/railties-3.2.6/lib/rails/commands/console.rb:47:in `start'
	from /app/vendor/bundle/ruby/1.9.1/gems/railties-3.2.6/lib/rails/commands/console.rb:8:in `start'
	from /app/vendor/bundle/ruby/1.9.1/gems/railties-3.2.6/lib/rails/commands.rb:41:in `<top (required)>'
	from script/rails:6:in `require'
	from script/rails:6:in `<main>'