Fix typo in README.md

Author: danpolyuha

README.md

@@ -1,6 +1,6 @@
 # Solid Cache
 
-Solid Cache is a database-backed Active Support cache store that let's you keep a much larger cache than is typically possible with traditional memory-only Redis or Memcached stores. This is thanks to the speed of modern SSD drives, which make the access-time penalty of using disk vs RAM insignificant for most caching purposes. Simply put, you're now usually better off keeping a huge cache on disk rather than a small cache in memory.
+Solid Cache is a database-backed Active Support cache store that lets you keep a much larger cache than is typically possible with traditional memory-only Redis or Memcached stores. This is thanks to the speed of modern SSD drives, which make the access-time penalty of using disk vs RAM insignificant for most caching purposes. Simply put, you're now usually better off keeping a huge cache on disk rather than a small cache in memory.
 
 ## Installation