Add progress_bar helper

[claudiob]

This stems from the amazing work of @buren (buren@a8ad37c and buren@fb75487) applying the comments listed at #15

The syntax for progress bar would be the following. Thumbs up @buren ?

Basic

<%= progress_bar %>

<%= progress_bar percentage: 60 %>

With label

<%= progress_bar percentage: 60, label: true %>

<%= progress_bar percentage: 60, label: "two thirds completed" %>

Low percentages

(nothing to do)


<%= progress_bar percentage: 0, label: true %>


<%= progress_bar percentage: 2, label: true %>

Context

<%= progress_bar percentage: 60, context: :success %>

Striped

<%= progress_bar percentage: 60, striped: true %>

Animated

<%= progress_bar percentage: 60, animated: true %>

Stacked

<%= progress_bar [{percentage: 30, context: :success}, {percentage: 40, context: :warning}] %>

[coveralls]

Coverage remained the same when pulling 39e5055 on claudiob:add-progress-bar into 7e66ad0 on Fullscreen:master.

[coveralls]

Coverage remained the same when pulling 69ccfb0 on claudiob:add-progress-bar into 7e66ad0 on Fullscreen:master.

[claudiob]

@buren And here is the documentation (to be merged after this PR goes into master) > http://claudiob.github.io/bh/#progress_bars

[buren]

👍