field :name, type: String, localized: true
    validates_uniqueness_of :name

`"$or"=>[{"name.en"=>"My name"}]`

`"$or"=>[]`

2015-04-29 08:34:14.177 FATAL 
Moped::Errors::QueryFailure - The operation: #<Moped::Protocol::Query
  @length=154
  @request_id=165
  @response_to=0
  @op_code=2004
  @flags=[]
  @full_collection_name="my_database.shops"
  @skip=0
  @limit=1
  @selector={"$or"=>[], :_id=>{"$ne"=>"5411425b6f295806f5001cdf"}}
  @fields={:_id=>1}>
failed with error 17287: "Can't canonicalize query: BadValue $and/$or/$nor must be a nonempty array"

See https://github.com/mongodb/mongo/blob/master/docs/errors.md
for details about this error.:
  moped (1.5.2) lib/moped/node.rb:384:in `block in query'
  moped (1.5.2) lib/moped/node.rb:589:in `block (3 levels) in flush'
  moped (1.5.2) lib/moped/node.rb:588:in `block (2 levels) in flush'
  moped (1.5.2) lib/moped/node.rb:150:in `ensure_connected'
  moped (1.5.2) lib/moped/node.rb:584:in `block in flush'
  moped (1.5.2) lib/moped/node.rb:599:in `logging'
  moped (1.5.2) lib/moped/node.rb:583:in `flush'
  moped (1.5.2) lib/moped/node.rb:572:in `process'
  moped (1.5.2) lib/moped/node.rb:372:in `query'
  moped (1.5.2) lib/moped/cursor.rb:138:in `block in load_docs'
  moped (1.5.2) lib/moped/session/context.rb:109:in `block in with_node'
  moped (1.5.2) lib/moped/cluster.rb:209:in `block in with_primary'
  moped (1.5.2) lib/moped/node.rb:197:in `ensure_primary'
  moped (1.5.2) lib/moped/cluster.rb:208:in `with_primary'
  moped (1.5.2) lib/moped/session/context.rb:108:in `with_node'
  moped (1.5.2) lib/moped/cursor.rb:137:in `load_docs'
  moped (1.5.2) lib/moped/cursor.rb:25:in `each'
  moped (1.5.2) lib/moped/query.rb:76:in `each'
  mongoid (3.1.6) lib/mongoid/contextual/mongo.rb:423:in `check_existence'
  mongoid (3.1.6) lib/mongoid/contextual/mongo.rb:146:in `exists?'
  C:0:in `exists?'
  mongoid (3.1.6) lib/mongoid/validations/uniqueness.rb:273:in `validate_root'
  mongoid (3.1.6) lib/mongoid/validations/uniqueness.rb:52:in `block in validate_each'
  mongoid (3.1.6) lib/mongoid/validations/queryable.rb:23:in `with_query'
  mongoid (3.1.6) lib/mongoid/validations/uniqueness.rb:46:in `validate_each'
  activemodel (3.2.20) lib/active_model/validator.rb:153:in `block in validate'
  activemodel (3.2.20) lib/active_model/validator.rb:150:in `validate'
  activesupport (3.2.20) lib/active_support/callbacks.rb:310:in `_callback_before_23394'
  activesupport (3.2.20) lib/active_support/callbacks.rb:814:in `_run__43917789__validate__1737515264__callbacks'
  activesupport (3.2.20) lib/active_support/callbacks.rb:405:in `__run_callback'
  activesupport (3.2.20) lib/active_support/callbacks.rb:385:in `_run_validate_callbacks'
  activesupport (3.2.20) lib/active_support/callbacks.rb:81:in `run_callbacks'
  mongoid (3.1.6) lib/mongoid/callbacks.rb:130:in `run_callbacks'
  activemodel (3.2.20) lib/active_model/validations.rb:228:in `run_validations!'
  activemodel (3.2.20) lib/active_model/validations/callbacks.rb:53:in `block in run_validations!'
  activesupport (3.2.20) lib/active_support/callbacks.rb:535:in `_run__43917789__validation__1737515264__callbacks'
  activesupport (3.2.20) lib/active_support/callbacks.rb:405:in `__run_callback'
  activesupport (3.2.20) lib/active_support/callbacks.rb:385:in `_run_validation_callbacks'
  activesupport (3.2.20) lib/active_support/callbacks.rb:81:in `run_callbacks'
  mongoid (3.1.6) lib/mongoid/callbacks.rb:130:in `run_callbacks'
  activemodel (3.2.20) lib/active_model/validations/callbacks.rb:53:in `run_validations!'
  activemodel (3.2.20) lib/active_model/validations.rb:195:in `valid?'
  mongoid (3.1.6) lib/mongoid/validations.rb:84:in `valid?'
  activemodel (3.2.20) lib/active_model/validations.rb:203:in `invalid?'
  mongoid (3.1.6) lib/mongoid/persistence/modification.rb:22:in `prepare'
  mongoid (3.1.6) lib/mongoid/persistence/operations/update.rb:45:in `persist'
  mongoid (3.1.6) lib/mongoid/persistence.rb:150:in `update'
  mongoid (3.1.6) lib/mongoid/persistence.rb:87:in `save'
  mongoid (3.1.6) lib/mongoid/persistence.rb:186:in `update_attributes'
  my_route/shops_controller.rb:36:in `update'