Add ArgoCD for GitOps's CD part

Signed-off-by: Sahadat Hossain <shahincsejnu@gmail.com>

schemas/manifests/README.md

@@ -0,0 +1,35 @@
+# Manifests
+
+## Structure of this `manifests` directory
+- `argocd` folder contains the argocd application
+- `k8s` folder contains the kubernetes yaml files of our `gocom` project
+
+## Sequence of commands to apply the manifests
+- from `manifests` dir
+- `kubectl apply -f k8s/postgresql-db.yaml`
+    - apply the DB manifests and wait until DB becomes ready
+    - confirm by `kubectl get pods`
+- `kubectl apply -f k8s/auth.yaml`
+- `kubectl apply -f k8s/ecom.yaml`
+
+## Steps to trigger the GitOps's CD part by ArgoCD
+
+### For the First time (this is needed only once initially)
+- create `argocd` namespace: `kubectl create namespace argocd`
+- install `argocd`: `kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml`:
+    - make sure pods are running: `kubectl get pods -n argocd`
+    - check the services: `kubectl get svc -n argocd`
+- port forward of the `argocd` server (to access the `argocd` UI): `kubectl port-forward -n argocd svc/argocd-server 8080:443`
+- login to argocd UI(`localhost:8080`):
+    - username: `admin`
+    - password: get by `kubectl -n argocd get secret argocd-initial-admin-secret -o jsonpath="{.data.password}" | base64 -d; echo`
+- connect the git repository from argocd UI:
+    - go to repositories -> add github
+    - you may need to provide git personal access token for the respective git repo
+- apply argocd application: `kubectl apply -f argocd/application.yaml` 
+
+
+### From next time
+- open a PR for changing the manifests(basically update the `gocom` project's services's docker image in respective manifests from `k8s` directory)
+- when the PR get merged argocd will trigger the changes in the respective cluster
+> Note: argocd syncs in every 3minutes

schemas/manifests/argocd/application.yaml

@@ -0,0 +1,20 @@
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+metadata:
+  name: gocom-argocd-application
+  namespace: argocd
+spec:
+  project: default
+  source:
+    repoURL: https://github.com/shahincsejnu/gocom
+    path: schemas/manifests/k8s
+    targetRevision: HEAD
+  destination:
+    namespace: default
+    server: https://kubernetes.default.svc
+  syncPolicy:
+    syncOptions:
+      - CreateNamespace=true
+    automated:
+      prune: true
+      selfHeal: true