Updated links to use https

I just updated a few links to use https instead of http. 

Thank you! ^ _ ^
diff --git a/README.md b/README.md
index fca7d1c..f387b4b 100644
--- a/README.md
+++ b/README.md
@@ -198,8 +198,8 @@
 * [users.rust-lang.org] - General discussion and broader questions.
 * [/r/rust] - News and general discussion.
 
-[Stack Overflow]: http://stackoverflow.com/questions/tagged/rust
-[/r/rust]: http://reddit.com/r/rust
+[Stack Overflow]: https://stackoverflow.com/questions/tagged/rust
+[/r/rust]: https://reddit.com/r/rust
 [users.rust-lang.org]: https://users.rust-lang.org/
 
 ## Contributing