Add "git jira" command

The "git jira" command parses the branch name to determine the Jira
issue based on the naming schedule
{branchType}/{issue}-{description}
e.g. feature/sf-123-add-new-button (the issue number is "sf-123")

The git jira command uses this issue number in combination with the
custom git config value stored at 'salcode.jiraSubdomain' (in my example
this value is "ferrarello") to construct a
URL like

https://ferrarello.atlassian.net/browse/sf-123

and open this URL in the browser.

See #118

gitconfig

@@ -89,8 +89,9 @@
 		git cherry-pick @{-1}~${1:-1}...@{-1}~0;   \
 	}; f"
 
-	open = "!f() { \
-		echo https://webdevstudios.atlassian.net/browse/$(git rev-parse --abbrev-ref HEAD | sed 's/^.*\\/\\([a-zA-z]\\{1,\\}\\).*/\\1/'); \
+	jira = "!f() { \
+		jiraBaseUrl=\"https://$(git config --get salcode.jiraSubdomain).atlassian.net/browse/\"; \
+		open $jiraBaseUrl$(git rev-parse --abbrev-ref HEAD | sed 's/^.*\\/\\([a-zA-z]\\{1,\\}-[0-9]\\{1,\\}\\).*/\\1/'); \
 	}; f"
 
 	# Move to the given branch the last n commits.