update install instructions

README.md

@@ -31,9 +31,23 @@ IPDR is a [Docker Registry](https://docs.docker.com/registry/) tool that proxies
 
 ## Install
 
-```bash
-go install github.com/miguelmota/ipdr/cmd/ipdr
-```
+- Install with [Go](https://golang.org/doc/install):
+
+    ```bash
+    go get -u github.com/miguelmota/ipdr/cmd/ipdr
+    ```
+
+- Install from [release binaries](https://github.com/miguelmota/ipdr/releases)
+
+    ```bash
+# replace x.x.x with the latest version
+    wget https://github.com/miguelmota/ipdr/releases/download/x.x.x/ipdr_x.x.x_linux_amd64.tar.gz
+    tar -xvzf ipdr_x.x.x_linux_amd64.tar.gz ipdr
+    ./ipdr --help
+
+# move to bin path
+    sudo mv ipdr /usr/local/bin/ipdr
+    ```
 
 ## Getting started