Adding Any to IRedisCollecitonInterface (#58)

Author: slorello89

src/Redis.OM/Searching/IRedisCollection.cs

@@ -1,5 +1,7 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Linq;
+using System.Linq.Expressions;
 using System.Threading.Tasks;
 using Redis.OM.Modeling;
 
@@ -54,5 +56,12 @@ public interface IRedisCollection<T> : IOrderedQueryable<T>, IAsyncEnumerable<T>
         /// <param name="id">the id to lookup.</param>
         /// <returns>the item if it's present.</returns>
         T? FindById(string id);
+
+        /// <summary>
+        /// Checks to see if anything matching the expression exists.
+        /// </summary>
+        /// <param name="expression">the expression to be matched.</param>
+        /// <returns>Whether anything matching the expression was found.</returns>
+        bool Any(Expression<Func<T, bool>> expression);
     }
 }