TER-408 add git workflow doc

.github/workflows/README.md

@@ -0,0 +1,63 @@
+# Automaton flows on repository
+
+The Terrarium repo has various automation flows in place. Mainly there are three events that trigger the automation in this repo:
+
+1. New Pull request
+1. Merge to the base branch (main)
+1. Create new release tag (v*)
+
+## 1. New pull request
+
+The intent of automation pipelines here is to validate the changes coming from the pull requests.
+
+```mermaid
+flowchart LR
+  Code --> PR --> CH["Checks\nGitHub Action"]
+  PR --> CLI["CLI test automation\nCode Pipes"]
+  PR --> API["API test automation\nAZP"]
+  CH --> UT["Unit Test"]
+  CH --> ST["Smoke test\nAPI health-check & harvest flow"]
+```
+
+## 2. Merge to the base branch (main)
+
+There are two automation intents that run on merge to master:
+
+### 1. Validation
+
+This is same as the PR checks, but is important here to ensure sanity of the code merge.
+
+### 2. Build container images and deploy to staging
+
+The terrarium repo produces two docker images:
+
+- **docker.io/cldcvr/terrarium-api** - Terrarium API image is used to deploy the API server. It is based on alpine and contains the go binary for server.
+- **docker.io/cldcvr/terrarium-farm-harvester** - Terrarium Harvester image is based on terraform image and contains Terrarium CLI binary built in along with a Makefile that contains sequence of running the terraform harvest commands.
+
+```mermaid
+flowchart LR
+  Code --> Main --> H["Push harvester image\nGitHub Action\ncldcvr/terrarium-farm-harvester:latest,\ncldcvr/terrarium-farm-harvester:commit_sha"]
+  H --> F["Used in farm repo"]
+  Main --> API["Push API Image\nCode Pipes App Integration\ncldcvr/terrarium-api:latest,\ncldcvr/terrarium-api:commit_sha"]
+  API --> D["Deploy to Staging"]
+  Main --> C["Unit tests and integration test pipelines"]
+```
+
+## 3. Create new release tag (v*)
+
+The release process currently deals with releasing a new version of Terrarium CLI binary. The Terrarium API doesn't have a Prod release (or deployment) setup currently.
+
+```mermaid
+flowchart TD
+  Code --> PR["Create pre-release\neg tag v1.0.0"]
+  PR --> A["Build CLI binaries for multiple platforms\nGitHub Action pipeline"]
+  A --> U["Upload binaries to the GitHub Release"]
+  U --> GHL["Mark the GitHub release as latest"]
+  U --> HBA["Auto generate PR in Homebrew-tap repo\nfrom GitHub action"]
+  HBA --> HBL["Merge the PR to publish the\n latest CLI version on Homebrew-tap"]
+```
+
+When creating a new version release in GitHub, mark it as "Pre-release", then wait for the pipelines to finish, and you should see the release assets uploaded. Then make a business decision to publish the release, and do two things to publish the release:
+
+1. Label the GitHub release as "latest"
+2. Merge the auto generated PR in [homebrew-tap](https://github.com/cldcvr/homebrew-tap) repo. - This step is responsible for publishing the new version in Homebrew for all the users that use Homebrew for CLI installation

.github/workflows/build-n-push.yaml

@@ -1,4 +1,4 @@
-name: Build and Push to DockerHub
+name: Push Harvester Image
 
 on:
   push: