fixes

lib/services/db.js

@@ -199,13 +199,19 @@ DB.prototype.getBlock = function(hash, callback) {
   });
 };
 
+/**
+ * get block hashes between two timestamps
+ * @param {Number} start - first timestamp, in seconds, inclusive
+ * @param {Number} end - second timestamp, in seconds, inclusive
+ * @param {Function} callback
+ */
 DB.prototype.getBlockHashesByTimestamp = function(start, end, callback) {
   var self = this;
   var hashes = [];
 
   var stream = this.store.createReadStream({
-    start: this._encodeBlockIndexKey(start),
-    end: this._encodeBlockIndexKey(end),
+    gte: this._encodeBlockIndexKey(start),
+    lte: this._encodeBlockIndexKey(end),
     valueEncoding: 'binary',
     keyEncoding: 'binary'
   });