Merge pull request #962 from danger/test_types

Adds gitlab docs

docs/usage/gitlab.html.md

@@ -0,0 +1,35 @@
+---
+title: Danger + GitLab
+subtitle: Self-Hosted
+layout: guide_js
+order: 4
+blurb: An overview of using Danger with GitLab, and some examples
+---
+
+To use Danger JS with GitLab: you'll need to create a new account for Danger to use, then set the following environment
+variables on your CI system:
+
+- `DANGER_GITLAB_HOST` = Defaults to `https://gitlab.com` but you can use it for your own url
+- `DANGER_GITLAB_API_TOKEN` = An access token for the account which will post comments
+
+Then in your Dangerfiles you will have a fully fleshed out `danger.gitlab` object to work with. For example:
+
+```ts
+import { danger, warn } from "danger"
+
+if (danger.bitbucket_cloud.mr.title.includes("WIP")) {
+  warn("PR is considered WIP")
+}
+```
+
+The DSL is expansive, you can see all the details inside the [Danger JS Reference][ref], but the TLDR is:
+
+```ts
+danger.gitlab.
+  /** The pull request and repository metadata */
+  metadata: RepoMetaData
+  /** The Merge Request metadata */
+  mr: BitBucketCloudPRDSL
+  /** The commits associated with the merge request */
+  commits: BitBucketCloudCommit[]
+```