store blockchain into data file, read blockchain.data on peer poweron. frontend: cssMaterialColors added as a bower external package

peer/blockchain.data

@@ -0,0 +1 @@
+{"genesisblock":"YKWAWY6GM5xrLhYrfi6hAmPmsECUH83n7xVcgaguLF4=","lastupdate":"0001-01-01T00:00:00Z","blocks":[{"hash":"YKWAWY6GM5xrLhYrfi6hAmPmsECUH83n7xVcgaguLF4=","height":0,"date":"2017-11-29T10:42:55.112675187+01:00","previoushash":"","nexthash":"","data":[{"address":"firstaddress"}],"emitter":"VOnL-15rFsUiCnRoyGFksKvWKcwNBRz5iarRem0Ilvo="}]}

peer/blockchain.go

@@ -75,6 +75,8 @@ func (bc *Blockchain) addBlock(block Block) error {
 	}
 	bc.Blocks = append(bc.Blocks, block)
 
+	bc.saveToDisk()
+
 	return nil
 }
 
@@ -129,3 +131,25 @@ func (bc *Blockchain) print() {
 		color.Green("---")
 	}
 }
+
+func (bc *Blockchain) readFromDisk() error {
+	file, err := ioutil.ReadFile("blockchain.data")
+	if err != nil {
+		return err
+	}
+	content := string(file)
+	json.Unmarshal([]byte(content), &bc)
+	return nil
+}
+
+func (bc *Blockchain) saveToDisk() error {
+	bytesBlockchain, err := json.Marshal(blockchain)
+	if err != nil {
+		return err
+	}
+	err = ioutil.WriteFile("blockchain.data", bytesBlockchain, 0644)
+	if err != nil {
+		return err
+	}
+	return nil
+}

peer/main.go

@@ -32,6 +32,11 @@ func main() {
 	//read configuration file
 	readConfig("config.json")
 
+	//read the stored blockchain
+	err := blockchain.readFromDisk()
+	check(err)
+	blockchain.print()
+
 	//runningPeer.ID = strconv.Itoa(randInt(1, 1000)) //0 is reserved for server
 	runningPeer.IP = config.IP
 	runningPeer.Port = config.Port