Add cheatsheet for scd

`scd` is a fantastic `oh-my-zsh` plugin to quickly jump between directories.
See here: https://github.com/robbyrussell/oh-my-zsh/tree/master/plugins/scd

cheat/cheatsheets/scd

@@ -0,0 +1,20 @@
+# Index recursively some paths for the very first run
+scd -ar ~/Documents/
+
+# Change to a directory path matching "doc"
+scd doc
+
+# Change to a path matching all of "a", "b" and "c"
+scd a b c
+
+# Change to a directory path that ends with "ts"
+scd "ts$"
+
+# Show selection menu and ranking of 20 most likely directories
+scd -v
+
+# Alias current directory as "xray"
+scd --alias=xray
+
+# Jump to a previously defined aliased directory
+scd xray