Adding getIpFromRequest method to get the request's IP (#84)

* Adding getIpFromRequest method to get the request's IP

lib/rate-limiter.guard.ts

@@ -166,12 +166,16 @@ export class RateLimiterGuard implements CanActivate {
 		const response = this.httpHandler(context).res
 
 		const rateLimiter: RateLimiterAbstract = await this.getRateLimiter(reflectedOptions)
-		const key = request.ip?.match(/\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b/)?.[0]
+		const key = this.getIpFromRequest(request)
 
 		await this.responseHandler(response, key, rateLimiter, points, pointsConsumed)
 		return true
 	}
 
+	protected getIpFromRequest(request: { ip: string }): string {
+	        return request.ip?.match(/\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b/)?.[0]
+	}
+
 	private httpHandler(context: ExecutionContext) {
 		if (this.options.for === 'ExpressGraphql') {
 			return {