Fixed some folders not getting created on fresh installs, throwing a few errors

lib/npmPostinstall.js

@@ -0,0 +1,18 @@
+var mkdirp = require("mkdirp");
+
+var directories = [
+	"database/linvodb",
+	"sharedMods",
+	"instances",
+];
+
+directories.forEach(path => {
+	mkdirp("database/linvodb", function(err){
+		if(err){
+			console.error("Unable to mkdirp "+path);
+			console.error(err);
+		} else {
+			console.log("mkdirp "+path);
+		}
+	});
+})

package.json

@@ -1,6 +1,6 @@
 {
   "name": "clusterio",
-  "version": "1.7.1",
+  "version": "1.7.0",
   "description": "Interserver communication for factorio",
   "repository": "https://github.com/Danielv123/factorioClusterio",
   "main": "master.js",
@@ -9,7 +9,8 @@
     "start": "echo Run node client.js start [instance] to start slaves && node master.js",
     "cover": "./node_modules/.bin/istanbul cover ./node_modules/mocha/bin/_mocha -- \"./{,!(node_modules)/**/}*.spec.js\" -R spec || echo . && codecov -t f7b38085-36eb-4d72-84e6-64721910171e",
     "docs": "documentation build index.js --config documentation.yml -f html -o docs",
-    "livedocs": "documentation serve --watch *.js lib/** --config documentation.yml"
+    "livedocs": "documentation serve --watch *.js lib/** --config documentation.yml",
+    "install": "node lib/npmPostinstall.js"
   },
   "keywords": [
     "factorio"