Backend cleanup (#146)

* Add ServerRegistration, begin refactoring to match frontend

* move graphData logic into ServerRegistration

* move ping updates/history into ServerRegistration

* start updating main app entry methods

* fix default rates.updateMojangStatus

* fix record loading delays on freshly booted instances

* move database loading logic to method + callback

* use data in frontend for type lookup instead of ping

* cleanup app.js

* reorganize methods to improve flow

* avoid useless mojang updates, remove legacy fields

* rename legacy fields for consistency

* finish restructure around App model

* ensure versions are sorted by release order

* filter errors sent to frontend to avoid data leaks

* fix version listing behavior on frontend

* 5.1.0

main.js

@@ -0,0 +1,36 @@
+const App = require('./lib/app')
+const ServerRegistration = require('./lib/servers')
+
+const logger = require('./lib/logger')
+
+const config = require('./config')
+const servers = require('./servers')
+
+const app = new App()
+
+servers.forEach(server => {
+  // Assign a generated color for each servers.json entry if not manually defined
+  // These will be passed to the frontend for use in rendering
+  if (!server.color) {
+    let hash = 0
+    for (let i = server.name.length - 1; i >= 0; i--) {
+      hash = server.name.charCodeAt(i) + ((hash << 5) - hash)
+    }
+
+    const color = Math.floor(Math.abs((Math.sin(hash) * 10000) % 1 * 16777216)).toString(16)
+    server.color = '#' + Array(6 - color.length + 1).join('0') + color
+  }
+
+  // Init a ServerRegistration instance of each entry in servers.json
+  app.serverRegistrations.push(new ServerRegistration(server))
+})
+
+if (!config.logToDatabase) {
+  logger.log('warn', 'Database logging is not enabled. You can enable it by setting "logToDatabase" to true in config.json. This requires sqlite3 to be installed.')
+
+  app.handleReady()
+} else {
+  app.loadDatabase(() => {
+    app.handleReady()
+  })
+}