Update CONTRIBUTING w/ production mode instruction (#15)

CONTRIBUTING.md

@@ -24,6 +24,7 @@ If you're on a Mac, you can run the following commands to install the necessary
 ```bash
 brew install node
 npm install -g @angular/cli@14.1.3
+npm install -g yarn
 
 brew install go
 
@@ -77,7 +78,7 @@ Next we'll start the processes described above:
 
 # In terminal #1, run the following
 cd frontend 
-npm run dist -- -c sandbox
+yarn dist -- -c [sandbox|prod]
 
 # In terminal #2, run the following
 go mod vendor
@@ -85,6 +86,8 @@ go run backend/cmd/fasten/fasten.go start --config ./config.dev.yaml --debug
 
 ```
 
+_Note_: Fasten can run in 2 modes: sandbox or production (prod). In sandbox mode, it can only communicate with test servers (full of synthetic health data).
+
 Now you can open a browser to `http://localhost:9090` to see the Fasten UI. 
 
 ## Important URL's 

frontend/.gitignore

@@ -44,3 +44,4 @@ testem.log
 # System Files
 .DS_Store
 Thumbs.db
+.angular