add external selection

src/main/java/com/mattmalec/pterodactyl4j/application/entities/PteroApplication.java

@@ -76,6 +76,23 @@ default PteroAction<ApplicationUser> retrieveUserById(long id) {
 		return retrieveUserById(Long.toUnsignedString(id));
 	}
 
+	/**
+	 * Retrieves an individual ApplicationUser represented by the provided External ID from Pterodactyl instance
+	 * <br>This requires an <b>Application API key</b> with the <b>Users</b> permission with <b>Read</b> access.
+	 *
+	 * @param  id
+	 *         The user's external ID
+	 *
+	 * @throws com.mattmalec.pterodactyl4j.exceptions.LoginException
+	 *         If the API key is incorrect or doesn't have the required permissions
+	 *
+	 * @throws com.mattmalec.pterodactyl4j.exceptions.NotFoundException
+	 *         If the user cannot be found
+	 *
+	 * @return {@link com.mattmalec.pterodactyl4j.PteroAction PteroAction} - Type {@link com.mattmalec.pterodactyl4j.application.entities.ApplicationUser ApplicationUser}
+	 */
+	PteroAction<ApplicationUser> retrieveUserByExternalId(String id);
+
 	/**
 	 * Retrieves ApplicationUsers matching the provided username from Pterodactyl instance
 	 * <br>This requires an <b>Application API key</b> with the <b>Users</b> permission with <b>Read</b> access.
@@ -538,6 +555,23 @@ default PteroAction<ApplicationServer> retrieveServerById(long id) {
 		return retrieveServerById(Long.toUnsignedString(id));
 	}
 
+	/**
+	 * Retrieves an individual ApplicationServer represented by the provided External ID from Pterodactyl instance
+	 * <br>This requires an <b>Application API key</b> with the <b>Servers</b> permission with <b>Read</b> access.
+	 *
+	 * @param  id
+	 *         The server's external ID
+	 *
+	 * @throws com.mattmalec.pterodactyl4j.exceptions.LoginException
+	 *         If the API key is incorrect or doesn't have the required permissions
+	 *
+	 * @throws com.mattmalec.pterodactyl4j.exceptions.NotFoundException
+	 *         If the server cannot be found
+	 *
+	 * @return {@link com.mattmalec.pterodactyl4j.PteroAction PteroAction} - Type {@link com.mattmalec.pterodactyl4j.application.entities.ApplicationServer ApplicationServer}
+	 */
+	PteroAction<ApplicationServer> retrieveServerByExternalId(String id);
+
 	/**
 	 * Retrieves ApplicationServers matching the provided name from Pterodactyl instance
 	 * <br>This requires an <b>Application API key</b> with the <b>Servers</b> permission with <b>Read</b> access.

src/main/java/com/mattmalec/pterodactyl4j/application/entities/impl/PteroApplicationImpl.java

@@ -53,6 +53,13 @@ public PteroAction<ApplicationUser> retrieveUserById(String id) {
 				(response, request) -> new ApplicationUserImpl(response.getObject(), this));
 	}
 
+	public PteroAction<ApplicationUser> retrieveUserByExternalId(String id) {
+		return PteroActionImpl.onRequestExecute(
+				api,
+				Route.Users.GET_USER_EXTERNAL.compile(id),
+				(response, request) -> new ApplicationUserImpl(response.getObject(), this));
+	}
+
 	@Override
 	public PaginationAction<ApplicationUser> retrieveUsers() {
 		return PaginationResponseImpl.onPagination(
@@ -276,6 +283,15 @@ public PaginationAction<ApplicationServer> retrieveServers() {
 				api, Route.Servers.LIST_SERVERS.compile(), (object) -> new ApplicationServerImpl(this, object));
 	}
 
+	@Override
+	public PteroAction<ApplicationServer> retrieveServerByExternalId(String id) {
+		return PteroActionImpl.onRequestExecute(
+				api,
+				Route.Servers.GET_SERVER_EXTERNAL.compile(id),
+				(response, request) -> new ApplicationServerImpl(this, response.getObject())
+		);
+	}
+
 	@Override
 	public PteroAction<ApplicationServer> retrieveServerById(String id) {
 		return PteroActionImpl.onRequestExecute(

src/main/java/com/mattmalec/pterodactyl4j/requests/Route.java

@@ -29,6 +29,7 @@ public static class Users {
 
 		public static final Route LIST_USERS = new Route(GET, APPLICATION_PREFIX + "users?include=servers");
 		public static final Route GET_USER = new Route(GET, APPLICATION_PREFIX + "users/{user_id}?include=servers");
+		public static final Route GET_USER_EXTERNAL = new Route(GET, APPLICATION_PREFIX + "users/external/{external_id}?includes=servers");
 		public static final Route CREATE_USER = new Route(POST, APPLICATION_PREFIX + "users");
 		public static final Route EDIT_USER = new Route(PATCH, APPLICATION_PREFIX + "users/{user_id}");
 		public static final Route DELETE_USER = new Route(DELETE, APPLICATION_PREFIX + "users/{user_id}");
@@ -73,6 +74,8 @@ public static class Servers {
 				GET,
 				APPLICATION_PREFIX
 						+ "servers/{server_id}?include=allocations,user,subusers,nest,egg,location,node,databases");
+		public static final Route GET_SERVER_EXTERNAL =
+				new Route(GET, APPLICATION_PREFIX + "servers/external/{external_id}?include=allocations,user,subusers,nest,egg,location,node,databases" );
 		public static final Route UPDATE_SERVER_DETAILS =
 				new Route(PATCH, APPLICATION_PREFIX + "servers/{server_id}/details");
 		public static final Route UPDATE_SERVER_BUILD =