diff --git a/README.md b/README.md
index 2d9efc9..8c0e221 100644
--- a/README.md
+++ b/README.md
@@ -15,8 +15,7 @@
 By default, Android SDK is expected under `~/android/sdk`.
 It is possible to adapt this path in `local.properties` (not to be committed).
 
-
-### Usage
+### Setup
 
 If the current user id and group id are not 1000, it is required to define them using environment variables:
 
@@ -25,10 +24,21 @@
 export _GID="$(id -g)"
 ```
 
-The following command should build (if required) and start a shell session inside the container:
+Build the container image:
 
 ```
-docker-compose --compatibility run --rm default
+docker-compose --compatibility build $OS_LABEL
+```
+
+Where OS_LABEL can take any supported value:
+  - centos7
+
+### Usage
+
+The following command should  start a shell session inside the container:
+
+```
+docker-compose --compatibility run --rm $OS_LABEL
 ```
 
 From there, Gradle and Fastlane should work as expected:
diff --git a/docker-compose.yml b/docker-compose.yml
index 95e5caa..f8d3063 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -1,6 +1,6 @@
 version: '3'
 services:
-  default:
+  centos7:
     build: 
       context: lazyDir
       dockerfile: centos7.Dockerfile