docs(README): update docs

Author: mapaiva

README.md

@@ -7,7 +7,9 @@ A minimal library to manipulate VCard file using Golang. This library is based o
 ## Installation
 
 ```sh
-go get -u github.com/mapaiva/vcard-go
+git clone https://github.com/mapaiva/vcard-go.git
+cd vcard-go
+make install
 ```
 
 ## Usage
@@ -30,6 +32,18 @@ func main() {
 }
 ```
 
+## Testing
+
+```sh
+make test
+```
+
+## Lint
+
+```sh
+make lint
+```
+
 ## Documentation
 
 Complete documentation available on https://godoc.org/github.com/mapaiva/vcard-go.