Split Makefile tasks into backend and frontend

Makefile

@@ -1,6 +1,10 @@
-all:
+backend:
 	npm install && \
-		npm run build && \
+		npm run build
-		cd frontend && \
+
+frontend:
+	cd frontend && \
 		npm install && \
 		npm run build
+
+all: backend frontend

README.md

@@ -14,6 +14,12 @@ GPSTracker is a simple Webapp that consists of:
 
 ## Building the application
 
+Requirements:
+
+- `node`
+- `typescript`
+- `make`
+
 ```sh
 make
 ```
@@ -22,13 +28,10 @@ Or, if you want to build the backend and the frontend separately:
 
 ```sh
 # Backend
-npm install
+make backend
-npm run build
 
 # Frontend
-cd frontend
+make frontend
-npm install
-npm run build
 ```
 
 ## Configuration