Fixed scalability test for V13 version of the project (#750) (#754)

Upgraded to Gatling 3
Inlined request bodies
Fixed mostly combobox requests
Updated readme
Formatted the scala file

README.md

@@ -98,15 +98,15 @@ In order to run the scalability tests locally:
 1. Start a test from the command line:
 
     ```bash
-    mvn -Pscalability gatling:execute
+    mvn -Pscalability gatling:test
     ```
 
 1. Test results are stored into target folder (e.g. to ```target/gatling/BaristaFlow-1487784042461/index.html```)
 
 1. By default the scalability test starts 100 user sessions at a 100 ms interval for one repeat, all of which connect to a locally running Bakery app. These defaults can be overridden with the `gatling.sessionCount`, `gatling.sessionStartInterval` `gatling.sessionRepeats`, and `gatling.baseUrl` system properties. See an example execution for 300 users started within 50 s:
 
     ```bash
-    mvn -Pscalability gatling:execute -Dgatling.sessionCount=300 -Dgatling.sessionStartInterval=50
+    mvn -Pscalability gatling:test -Dgatling.sessionCount=300 -Dgatling.sessionStartInterval=50
     ```
 
 Note: If you run Bakery with an in-memory database (like H2, which is the default), it will logically use more memory than when using an external database (like PostgreSQL). It is recommend to run scalability tests for Bakery only after you have configured it to use an external database.

pom.xml

@@ -33,9 +33,9 @@
         <maven.clean.plugin.version>3.0.0</maven.clean.plugin.version>
         <maven.surefire.plugin.version>2.21.0</maven.surefire.plugin.version>
 
-        <gatling.version>2.3.1</gatling.version>
-        <gatling-plugin.version>2.2.4</gatling-plugin.version>
-        <scala-maven-plugin.version>3.3.2</scala-maven-plugin.version>
+        <gatling.version>3.0.2</gatling.version>
+        <gatling-plugin.version>3.0.1</gatling-plugin.version>
+        <scala-maven-plugin.version>3.4.4</scala-maven-plugin.version>
 
         <!-- Frontend -->
         <node.version>v8.1.2</node.version>