add mongodb dependency and configuration instructions

Created by: atfornes

README.md

@@ -5,6 +5,7 @@ An Ethereum dApp for aggregating peer review data.
 - node > 12.0 & npm 6.0
 - truffle suite
 - ganache
+- mongodb
 
 # Installation
 
@@ -14,6 +15,8 @@ Install all node dependencies by:
 npm install
 ```
 
+### Truffle
+
 If not available, install `truffle` globally by:
 ```
 npm install -g truffle
@@ -22,17 +25,35 @@ npm install -g truffle
 Also download and run Ganache from [here](https://www.trufflesuite.com/docs/ganache/quickstart);
 
 During workspace intialization, set the port to 8545.
+
+### MongoDB
+
+Install [mongoDB](https://www.mongodb.com/) for the server database.
+
 ## Smart Contract
 Compile and migrate contracts by:
 ```
 truffle migrate --network develop
 ```
 
+## Configure database connection
+Copy template configuration from `./server/config-template.js` to `./server/config.js`:
+
+```
+cp ./server/config-template.js ./server/config.js
+```
+
+and make sure you have mongodb listening at the `databaseURI` address of your `./server/config.js` configuration file. For instance. you can start your default mongodb in debian-like systems with `sudo systemctl start mongod`,  and set `databaseURI` to `mongodb://localhost:27017`.
+
+## Run backend
+
 Run the backend in development mode with:
 ```
 npm run dev
 ```
 
+## Run frontend
+
 Open a new terminal an start the client with:
 ```
 npm run client