docs: added docker configuration

server-configuration/staging.md

@@ -105,7 +105,7 @@ server {
     # domain name here
     server_name staging.cellar.social;
 
-    location /api {
+    location /api/ {
 	proxy_pass http://127.0.0.1:3000/;
 
 	proxy_set_header Host $http_host;
@@ -215,3 +215,22 @@ npm run start
 # Verify that cellar-api process is running
 pm2 list
 ```
+
+## Docker
+
+Under `otto` user:
+
+```bash
+# Install docker
+curl -fsSL https://get.docker.com | sudo sh
+
+# Add api user to the docker group so it can run docker without sudo rights
+sudo usermod -aG docker api
+```
+
+Under `api` user:
+
+```bash
+# Log in to docker group to avoid to log out and log in again
+newgrp docker
+```