feat(project): add pinned deployments to projects

Author: evansiroky

src/main/java/com/conveyal/datatools/manager/models/Project.java

@@ -63,6 +63,8 @@ public OtpServer retrieveServer(String name) {
     // and/or for applying a geographic filter when syncing with external feed registries.
     public Bounds bounds;
 
+    public String pinnedDeploymentId;
+
     public Project() {
         this.buildConfig = new OtpBuildConfig();
         this.routerConfig = new OtpRouterConfig();