[Airbrake] [Production] Duplicate entry '' for key 2

[alekpopovic]

Airbrake error: #6976
Airbrake project: moovies

Error type: Mysql2::Error
Error message: Duplicate entry '' for key 2
Where: customers#update
Occurred at: Oct 11, 2016 16:16:44 UTC
First seen at: Oct 11, 2016 16:16:44 UTC
Occurrences: 0 (0 since last deploy on <no information>)

URL: http://www.plush.be/fr/mon-compte/2819
File: [GEM_ROOT]/gems/mysql2-0.3.21/lib/mysql2/client.rb

Backtrace:

[GEM_ROOT]/gems/mysql2-0.3.21/lib/mysql2/client.rb:85:in _query
[GEM_ROOT]/gems/mysql2-0.3.21/lib/mysql2/client.rb:85:in query
[GEM_ROOT]/gems/activerecord-3.2.14/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:245:in block in execute
[GEM_ROOT]/gems/activerecord-3.2.14/lib/active_record/connection_adapters/abstract_adapter.rb:280:in block in log