docs: add comprehensive contributing guidelines and best practices

.github/pull_request_template.md

@@ -7,7 +7,7 @@ Please describe in a short paragraph what this PR is about.
 Before submitting this PR, please make sure that:
 
 - [ ] You created a dedicated branch based on the `canary` branch.
-- [ ] You have read the suggestions in the CONTRIBUTING.md file https://github.com/MkinG2k0/dokploy/blob/canary/CONTRIBUTING.md#pull-request
+- [ ] You have read the suggestions in the CONTRIBUTING.md file https://github.com/Dokploy/dokploy/blob/canary/CONTRIBUTING.md#pull-request
 - [ ] You have tested this PR in your local instance. If you have not tested it yet, please do so before submitting. This helps avoid wasting maintainers' time reviewing code that has not been verified by you.
 
 ## Issues related (if applicable)

CONTRIBUTING.md

@@ -132,6 +132,21 @@ If you want to test the webhooks on development mode using localtunnel, make sur
 pnpm dlx localtunnel --port 3000
 ```
 
+### Testing GitLab Webhooks
+
+To test GitLab webhook functionality locally:
+
+1. Configure a GitLab provider in Dokploy with a webhook secret
+2. Set up the webhook in your GitLab project (Settings → Webhooks):
+   - **Webhook URL:** Your localtunnel URL + `/api/deploy/gitlab`
+   - **Secret token:** Paste the webhook secret from your Dokploy GitLab provider
+   - **Enable events:** Push events and Merge request events
+
+The GitLab webhook endpoint (`/api/deploy/gitlab`) authenticates requests via the `X-Gitlab-Token` header matched against the provider's `webhookSecret`. The endpoint handles:
+
+- **Push Hooks** — deploys matching applications and compose stacks; respects `watchPaths` filtering using commit file lists (added/modified/removed)
+- **Merge Request Hooks** — creates or rebuilds preview deployments on `open/update/reopen/labeled` events; tears down preview deployments on `close/merge` events
+
 If you run into permission issues of docker run the following command
 
 ```bash