Multi-provider auth. LDAP is not reworked
Supporting for multiple omniauth provider for the same user
added helper
Handle web hook exception

Write to log if web hook cant be executed. This prevents 500 error when
test web hook with invalid URL and prevent exceptions and retries in
sidekiq

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
fix specs
Merge branch 'multi_provider' into 'master'

Supporting for multiple omniauth provider for the same user

fixes https://dev.gitlab.org/gitlab/gitlabhq/issues/1721

and https://dev.gitlab.org/gitlab/gitlabhq/issues/1760

See merge request !1296
Merge branch 'prevent-500-test-webhook' into 'master'

Prevent 500 test webhook

Fixes #1803

See merge request !1299