Switch to rust docker image

Jenkinsfile

@@ -3,12 +3,20 @@ pipeline {
 
     stages {
         stage('Build') {
+            agent {
+                docker { image 'rust:alpine' }
+            }
+
             steps {
                 sh 'cargo b --release'
                 archiveArtifacts artifacts: '/target/school_app_api', fingerprint: true 
             }
         }
         stage('Test') {
+            agent {
+                docker { image 'rust:alpine' }
+            }
+
             steps {
                 sh 'cargo test'
             }