Pushover Webhook fails on first activation
### Summary
When I activate the Pushover Webhook, the Server returns an error (500). To solve this you have to push a commit to the Repo. After that the integration works just fine.
### Steps to reproduce
Create a Project and activate Pushover Plugin
### What is the current *bug* behavior?
An error message occures (server returns code 500)
### What is the expected *correct* behavior?
Redirect to settings page and show a success message (and a notification on your phone from Pushover)
#### Results of GitLab environment info
<details>
<summary>Expand for output related to GitLab environment info</summary>
<pre>
root@git:/# gitlab-rake gitlab:env:info
System information
System:
Current User: git
Using RVM: no
Ruby Version: 2.5.3p105
Gem Version: 2.7.9
Bundler Version:1.17.3
Rake Version: 12.3.2
Redis Version: 3.2.12
Git Version: 2.21.0
Sidekiq Version:5.2.7
Go Version: unknown
GitLab information
Version: 11.11.0-rc1
Revision: 204dca4436f
Directory: /opt/gitlab/embedded/service/gitlab-rails
DB Adapter: PostgreSQL
DB Version: 9.6.11
URL: http://git.kara-software.at
HTTP Clone URL: http://git.kara-software.at/some-group/some-project.git
SSH Clone URL: git@git.kara-software.at:some-group/some-project.git
Using LDAP: no
Using Omniauth: yes
Omniauth Providers:
GitLab Shell
Version: 9.0.0
Repository storage paths:
- default: /var/opt/gitlab/git-data/repositories
GitLab Shell path: /opt/gitlab/embedded/service/gitlab-shell
Git: /opt/gitlab/embedded/bin/git
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</details>
#### Results of GitLab application Check
<details>
<summary>Expand for output related to the GitLab application check</summary>
<pre>
Checking GitLab subtasks ...
Checking GitLab Shell ...
GitLab Shell: ... GitLab Shell version >= 9.0.0 ? ... OK (9.0.0)
Running /opt/gitlab/embedded/service/gitlab-shell/bin/check
Check GitLab API access: OK
Redis available via internal API: OK
Access to /var/opt/gitlab/.ssh/authorized_keys: OK
gitlab-shell self-check successful
Checking GitLab Shell ... Finished
Checking Gitaly ...
Gitaly: ... default ... OK
Checking Gitaly ... Finished
Checking Sidekiq ...
Sidekiq: ... Running? ... yes
Number of Sidekiq processes ... 1
Checking Sidekiq ... Finished
Checking Incoming Email ...
Incoming Email: ... Reply by email is disabled in config/gitlab.yml
Checking Incoming Email ... Finished
Checking LDAP ...
LDAP: ... LDAP is disabled in config/gitlab.yml
Checking LDAP ... Finished
Checking GitLab App ...
Git configured correctly? ... yes
Database config exists? ... yes
All migrations up? ... yes
Database contains orphaned GroupMembers? ... no
GitLab config exists? ... yes
GitLab config up to date? ... yes
Log directory writable? ... yes
Tmp directory writable? ... yes
Uploads directory exists? ... yes
Uploads directory has correct permissions? ... yes
Uploads directory tmp has correct permissions? ... yes
Init script exists? ... skipped (omnibus-gitlab has no init script)
Init script up-to-date? ... skipped (omnibus-gitlab has no init script)
Projects have namespace: ...
5/1 ... yes
3/2 ... yes
5/3 ... yes
3/4 ... yes
3/5 ... yes
3/7 ... yes
3/8 ... yes
5/9 ... yes
3/10 ... yes
5/13 ... yes
2/14 ... yes
5/15 ... yes
5/16 ... yes
5/17 ... yes
3/18 ... yes
5/19 ... yes
3/20 ... yes
11/21 ... yes
3/22 ... yes
5/23 ... yes
5/24 ... yes
3/25 ... yes
3/26 ... yes
5/27 ... yes
5/28 ... yes
5/29 ... yes
2/30 ... yes
Redis version >= 2.8.0? ... yes
Ruby version >= 2.5.3 ? ... yes (2.5.3)
Git version >= 2.21.0 ? ... yes (2.21.0)
Git user has default SSH configuration? ... yes
Active users: ... 9
Checking GitLab App ... Finished
Checking GitLab subtasks ... Finished
</pre>
</details>
issue