Update README.md

Author: denis256

README.md

@@ -2,6 +2,11 @@
 
 Common code used in Go projects
 
+Usage:
+```
+go get github.com/unidev-platform/golang-core
+```
+
 Important directories:
   * `xfiles` - file related utilities
   * `xcollection` - collections related functions
@@ -22,4 +27,4 @@ License
     distributed under the License is distributed on an "AS IS" BASIS,
     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     See the License for the specific language governing permissions and
-    limitations under the License.
+    limitations under the License.