feat(auth): implement user authentication system

backend/node_modules/has-flag/index.d.ts

@@ -0,0 +1,39 @@
+/**
+Check if [`argv`](https://nodejs.org/docs/latest/api/process.html#process_process_argv) has a specific flag.
+
+@param flag - CLI flag to look for. The `--` prefix is optional.
+@param argv - CLI arguments. Default: `process.argv`.
+@returns Whether the flag exists.
+
+@example
+```
+// $ ts-node foo.ts -f --unicorn --foo=bar -- --rainbow
+
+// foo.ts
+import hasFlag = require('has-flag');
+
+hasFlag('unicorn');
+//=> true
+
+hasFlag('--unicorn');
+//=> true
+
+hasFlag('f');
+//=> true
+
+hasFlag('-f');
+//=> true
+
+hasFlag('foo=bar');
+//=> true
+
+hasFlag('foo');
+//=> false
+
+hasFlag('rainbow');
+//=> false
+```
+*/
+declare function hasFlag(flag: string, argv?: string[]): boolean;
+
+export = hasFlag;