Merge pull request #1230 from Bash-it/feature/add-crystal

Add Crystal auto-completion on Mac

completion/available/crystal.completion.bash

@@ -0,0 +1,11 @@
+if which crystal >/dev/null 2>&1; then
+
+  if which brew >/dev/null 2>&1; then
+    BREW_PREFIX=$(brew --prefix)
+
+    if [ -f "$BREW_PREFIX"/etc/bash_completion.d/crystal ]; then
+      . "$BREW_PREFIX"/etc/bash_completion.d/crystal
+    fi
+  fi
+
+fi