Add gitmessage

Adds a default commit template wtih some helpful reminders for
writing good commit messages.

tag-git/gitconfig

@@ -46,6 +46,7 @@
 	untracked = cyan
 
 [commit]
+	template = ~/.gitmessage
 	verbose = true
 
 [core]

tag-git/gitmessage

@@ -0,0 +1,16 @@
+
+
+# 50-character subject line
+#
+# 72-character wrapped longer description. This should answer:
+#
+# * Why was this change necessary?
+# * How does it address the problem?
+# * Are there any side effects?
+#
+# Include a link to the ticket, if any.
+#
+# Add co-authors if you worked on this code with others:
+#
+# Co-authored-by: Full Name <email@example.com>
+# Co-authored-by: Full Name <email@example.com>