Initialisation

Added the packages and files for the backend server

node_modules/graphql/validation/rules/LoneSchemaDefinitionRule.d.ts

@@ -0,0 +1,10 @@
+import type { ASTVisitor } from '../../language/visitor';
+import type { SDLValidationContext } from '../ValidationContext';
+/**
+ * Lone Schema definition
+ *
+ * A GraphQL document is only valid if it contains only one schema definition.
+ */
+export declare function LoneSchemaDefinitionRule(
+  context: SDLValidationContext,
+): ASTVisitor;