Add compression

Related: simcaq/SCRUM#477

src/libs/app.js

@@ -4,6 +4,7 @@ const bodyParser = require('body-parser');
 const methodOverride = require('method-override');
 const cors = require('cors');
 const squel = require('squel');
+const compression = require('compression');
 
 const libs = `${process.cwd()}/libs`;
 
@@ -25,6 +26,7 @@ const db = mongoose();
 
 require(`${libs}/middlewares/passport`);
 
+app.use(compression({level: 6}));
 app.use(bodyParser.json({limit: '50mb'}));
 app.use(bodyParser.urlencoded({ extended: true, limit: '50mb' }));
 app.use(cookieParser());