Added runner card get endpoints

ref #77

src/errors/RunnerCardErrors.ts

@@ -0,0 +1,25 @@
+import { IsString } from 'class-validator';
+import { NotAcceptableError, NotFoundError } from 'routing-controllers';
+
+/**
+ * Error to throw when a card couldn't be found.
+ */
+export class RunnerCardNotFoundError extends NotFoundError {
+	@IsString()
+	name = "RunnerCardNotFoundError"
+
+	@IsString()
+	message = "Card not found!"
+}
+
+/**
+ * Error to throw when two cards' ids don't match.
+ * Usually occurs when a user tries to change a card's id.
+ */
+export class RunnerCardIdsNotMatchingError extends NotAcceptableError {
+	@IsString()
+	name = "RunnerCardIdsNotMatchingError"
+
+	@IsString()
+	message = "The ids don't match! \n And if you wanted to change a cards's id: This isn't allowed"
+}