diff --git a/Dockerfile b/Dockerfile
index e42c132..07f502e 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -44,7 +44,7 @@ RUN mv /screeps/assets /data/assets && \
 WORKDIR /screeps
 COPY screeps-cli.js ./bin/cli
 COPY screeps-start.js ./bin/start
-ENV SERVER_DIR=/screeps NODE_ENV=production PATH="/screeps/bin:${PATH}"
+ENV SERVER_DIR=/screeps DATA_DIR=/data NODE_ENV=production PATH="/screeps/bin:${PATH}"
 
 VOLUME [ "/data" ]
 EXPOSE 21025
diff --git a/screeps-start.js b/screeps-start.js
index d023b8b..313727d 100755
--- a/screeps-start.js
+++ b/screeps-start.js
@@ -8,7 +8,12 @@ const RootDir = process.env["SERVER_DIR"];
 if (!RootDir) {
   throw new Error("Missing environment variable $SERVER_DIR");
 }
-const ConfigPath = process.env["CONFIG_FILE"] || "./config.yml";
+const DataDir = process.env["DATA_DIR"];
+if (!DataDir) {
+  throw new Error("Missing environment variable $DATA_DIR");
+}
+const ConfigPath =
+  process.env["CONFIG_FILE"] || path.join(RootDir, "config.yml");
 
 process.chdir(RootDir);
 
@@ -17,7 +22,7 @@ const config = yaml.load(fs.readFileSync(ConfigPath, "utf8"));
 const loadPackage = (dir) =>
   JSON.parse(fs.readFileSync(path.resolve(dir, "package.json"), "utf8"));
 
-const ModsDir = "./mods";
+const ModsDir = path.join(DataDir, "mods");
 
 const isDependency = (pkg, [name, version]) =>
   pkg.includes(name) || version.includes(pkg);
@@ -30,9 +35,9 @@ const installPackages = () => {
   const modsPackage = loadPackage(ModsDir);
   const dependencies = modsPackage.dependencies || {};
 
-  // Calculate package diff
   const packages = [...mods, ...Object.values(bots)];
 
+  // Calculate package diff
   const newPackages = packages.filter(
     (pkg) =>
       !Object.entries(dependencies).some((dependency) =>
@@ -81,12 +86,6 @@ const installPackages = () => {
     );
   }
 
-  const newPackage = loadPackage(ModsDir);
-  fs.writeFileSync(
-    path.resolve(ModsDir, "package.json"),
-    JSON.stringify(newPackage, null, 2),
-  );
-
   console.log("Done updating");
 };