create a proposed pipeline diagram (#68)

Author: duncancrawford

docs/PIPELINE.md

@@ -30,4 +30,34 @@ sequenceDiagram
     JFA->>Art: Upstream dependency
     ADO->>ACR: Build & publish container
 
+```
+
+## Proposed Pipeline
+
+This represents the next iteration of the pipeline, simplifying the process by removing Azure DevOps and JFrog Artifactory, 
+but more importantly allow the owners of the repository to have full control of the pipeline and publishing the actual artefact that they produce and is used.
+
+The GitHub Actions workflow will handle building and publishing both the application artefact and the Docker image to Azure Container Registry (ACR).
+
+```mermaid
+sequenceDiagram
+    participant Dev as Developer
+    participant Repo as (Micro)Service Repository
+    participant GH as GitHub Actions
+    participant Art as Azure Artifacts (Public)
+    participant ACR as Azure Container Registry
+
+    Dev->>Repo: Pull Request
+    Repo->>GH: Various Actions Workflows are triggered
+    note right of GH: Actions Workflows are run in parallel
+    GH->>GH: Security Scans (CodeQL, Trufflehog, Gitleaks)
+    GH->>GH: Linting & Static Code Analysis
+    GH->>GH: Unit & Integration Tests
+    GH->>GH: Build (Gradle)
+
+    note right of GH: All assurance workflow steps are complete
+    GH->>Art: Publish artefact [DRAFT] (versioned via git tag & commit SHA)
+    note right of GH: The build and publish of the image is one step via the<br/>custom action "docker/build-push-action" but is represented<br/>here as two steps for readability
+    GH->>GH: Build Docker image (versioned via git tag & commit SHA)
+    GH->>ACR: Publish container
 ```