Merge branch 'chruby-support' into 'master'

Adding chruby support

You know, I'm not using rbenv, cause it's too big for me. Tool called ```chruby``` is my choice, so I've added support for this tool in zsh-config.

See merge request !2

zsh/defaults/50-chruby.conf

@@ -0,0 +1,4 @@
+# chruby in use?
+USE_CHRUBY=0
+# Path to chruby scripts.
+CHRUBY_PATH="/usr/share/chruby"

zsh/exports/95-chruby.zsh

@@ -0,0 +1,10 @@
+# chruby sourcing.
+
+# This exports should work only if config states this.
+if [ "${USE_CHRUBY}" -eq 0 ]; then
+    return
+fi
+
+export CHRUBY_ROOT="${CHRUBY_PATH}"
+source "${CHRUBY_ROOT}/chruby.sh"
+source "${CHRUBY_ROOT}/auto.sh"