Add bash completion script for gerrit.sh

The script provides tab-completion in the bash shell for the gerrit.sh
script.

It can be invoked on a per-shell basis, or included in the user's bash
profile to be made available on every login.

Change-Id: I7f8afb8885d42c30df909a0520a0c736b8735fb4

contrib/bash_completion

@@ -0,0 +1,67 @@
+# The MIT License
+#
+# Copyright (C) 2013 Sony Mobile Communications. All rights reserved.
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+#
+# #########################################################################
+# This bash script adds tab-completion to the gerrit.sh script.
+#
+# Testing it out without installing
+# =================================
+#
+# To test out the completion without "installing" this, just run this file
+# directly, like so:
+#
+#     . ~/path/to/bash_completion
+#
+# Note: There's a dot ('.') at the beginning of that command.
+#
+# After you do that, tab completion will immediately be made available in your
+# current Bash shell. It will not, however, be available next time you log in.
+#
+# Installing
+# ==========
+#
+# To install the completion, point to this file from your .bash_profile, like so:
+#
+#     . ~/path/to/bash_completion
+#
+# Do the same in your .bashrc if .bashrc doesn't invoke .bash_profile.
+#
+# The settings will take effect the next time you log in.
+#
+# Uninstalling
+# ============
+#
+# To uninstall, just remove the line from your .bash_profile and .bashrc.
+# #########################################################################
+
+_gerrit_sh()
+{
+    local cur prev opts
+    COMPREPLY=()
+    cur="${COMP_WORDS[COMP_CWORD]}"
+    prev="${COMP_WORDS[COMP_CWORD-1]}"
+    opts="check restart run start status stop supervise"
+
+    COMPREPLY=( $(compgen -W "${opts}" -- ${cur}) )
+}
+complete -F _gerrit_sh gerrit.sh
+