added blank lines as needed

database/README.md

@@ -1,16 +1,23 @@
 # databases
 
 ## In-Memory Databases
+
 ### [redis](/redis/)
+
     https://redis.io/
 
 ## NoSQL
+
 ### [mongodb](/nosql/mongodb/)
+
     https://www.mongodb.com/
 
 ## SQL Databases
+
 ### [mariadb](/sql/mariadb/)
+
     https://mariadb.org/
 
 ### [postgres](/sql/postgres/)
-    https://www.postgresql.org/
+
+    https://www.postgresql.org/