Added Citations to Ruby.gitignore and Python.gitignore

I wanted to use these templates in my repository, so I felt responsible to cite the source in the comments.

Python.gitignore

@@ -1,3 +1,5 @@
+## Get latest from https://github.com/github/gitignore/
+
 # Byte-compiled / optimized / DLL files
 __pycache__/
 *.py[cod]

Ruby.gitignore

@@ -1,3 +1,5 @@
+## Get latest from https://github.com/github/gitignore/
+
 *.gem
 *.rbc
 /.config