refactor server code into a module

remix-simulator/bin/ethsim

@@ -1,4 +1,6 @@
 #!/usr/bin/env node
 
-require('../src/server');
+const Server = require('../src/server');
+const server = new Server()
+server.start()
 

remix-simulator/src/server.js

@@ -5,9 +5,14 @@ const expressWs = require('express-ws')
 const Provider = require('./provider')
 const log = require('./utils/logs.js')
 
-expressWs(app)
+class Server {
+
+  constructor() {
+    this.provider = new Provider()
+  }
 
-var provider = new Provider()
+  start(host, port) {
+    expressWs(app)
 
     app.use(bodyParser.urlencoded({extended: true}))
     app.use(bodyParser.json())
@@ -37,3 +42,8 @@ app.ws('/', (ws, req) => {
     })
 
     app.listen(8545, () => log('Remix Simulator listening on port 8545!'))
+  }
+
+}
+
+module.exports = Server