update README

Author: TasinIshmam

README.md

@@ -4,8 +4,12 @@ Tutorial for HowToGraphQL with Typescript, Apollo-Server, Nexus and Prisma.
 
 ### Installation
 
-1. Run `npm install`
-2. Run `npx prisma generate`
-3. Run `npm dev` 
+1. Install dependencies: `npm install`
+2. Start a PostgreSQL database with docker using: `docker-compose up -d`. 
+    - If you have a local instance of PostgreSQL running, you can skip this step. 
+3. Create a `.env` file and add the `DATABASE_URL` environment variable with a [PostgreSQL connection string](https://www.prisma.io/docs/concepts/database-connectors/postgresql#connection-details).
+    - The `.env.example` file is provided as reference. 
+4. Apply database migrations: `npx prisma migrate dev` 
+5. Start the project:  `npm dev` 
+
 
-_Note:_ There's no need to run migrations on the database because the SQLite Database is added to version control for convenience.