added info how to install lmdb

Asmod4n · Asmod4n · commit c9ee76cc8c21 · 2015-09-16T21:34:34.000+02:00
diff --git a/README.md b/README.md
@@ -5,6 +5,16 @@ Prerequisites
 =============
 lmdb needs to be somewhere your compiler can find it.
 
+On Ubuntu:
+```sh
+apt install liblmdb-dev
+```
+
+On OS X:
+```sh
+brew install lmdb
+```
+
 Examples
 ========
 
