Support Akismet spam checking for creation of issues via API

Currently any spam detected by Akismet by non-members via API will be logged
in a separate table in the admin page.

Closes #5612

3 files changed, 31 insertions, 0 deletions

diff --git a/doc/integration/README.md b/doc/integration/README.md
index 83116bc8370..281eea8363d 100644
--- a/doc/integration/README.md
+++ b/doc/integration/README.md
@@ -15,6 +15,7 @@ See the documentation below for details on how to configure these services.
 - [OAuth2 provider](oauth_provider.md) OAuth2 application creation
 - [Gmail actions buttons](gmail_action_buttons_for_gitlab.md) Adds GitLab actions to messages
 - [reCAPTCHA](recaptcha.md) Configure GitLab to use Google reCAPTCHA for new users
+- [Akismet](akismet.md) Configure Akismet to stop spam
 
 GitLab Enterprise Edition contains [advanced Jenkins support][jenkins].
 
diff --git a/doc/integration/akismet.md b/doc/integration/akismet.md
new file mode 100644
index 00000000000..5cc09bd536d
--- /dev/null
+++ b/doc/integration/akismet.md
@@ -0,0 +1,30 @@
+# Akismet
+
+GitLab leverages [Akismet](http://akismet.com) to protect against spam. Currently
+GitLab uses Akismet to prevent users who are not members of a project from
+creating spam via the GitLab API. Detected spam will be rejected, and
+an entry in the "Spam Log" section in the Admin page will be created.
+
+Privacy note: GitLab submits the user's IP and user agent to Akismet. Note that
+adding a user to a project will disable the Akismet check and prevent this
+from happening.
+
+## Configuration
+
+To use Akismet:
+
+1. Go to the URL: https://akismet.com/account/
+
+2. Sign-in or create a new account.
+
+3. Click on "Show" to reveal the API key.
+
+4. Go to Applications Settings on Admin Area (`admin/application_settings`)
+
+5. Check the `Enable Akismet` checkbox
+
+6. Fill in the API key from step 3.
+
+7. Save the configuration.
+
+![Screenshot of Akismet settings](img/akismet_settings.png)
diff --git a/doc/integration/img/akismet_settings.png b/doc/integration/img/akismet_settings.png
new file mode 100644
index 00000000000..ccdd3adb1c5
--- /dev/null
+++ b/doc/integration/img/akismet_settings.png