fix inconsistent variable names in usage example

Author: ayedo

README.md

@@ -45,15 +45,15 @@ dependencies {
 
 ## Usage
 
-    val databaseRestorer = DatabaseRestorer(
+    val restorer = DatabaseRestorer(
         databaseName = "postgres",
         host = "localhost",
         port = 5432,
         user = "postgres",
         password = "postgres"
     )
 
-    databaseRestorer.takeSnapshot()
+    restorer.takeSnapshot()
 
     // later call this to restore to the state when you called snapshot
     restorer.restore()