Hey, I’m new to middleman and ruby; fumbled my way through dynamic pages today and am running into an issue when I run middleman build. Everything works fine in localhost.
The error says "undefined method '[]' for nil:NilClass" when it tries to build the template file I’m using for my dynamic pages, followed by a whole lot of stuff I don’t understand 
I think this is the most relevant part as it calls out the template file name (I removed the path for this post):
/groups/gt.html.erb:2:in `block in singleton class'
/groups/gt.html.erb:131066:in `instance_eval'
/groups/gt.html.erb:131066:in `singleton class'
/groups/gt.html.erb:131064:in `__tilt_16951464'
Below are details on how my file is set up - thanks in advance to anyone who can help me understand what in tarnation is happening here.
I have a JSON file (allgroups.json) in the data directory that contains all the content for the dynamic pages I’m trying to build out. As an example, here is the structure:
{
"groups" : [
{
"slug":"slug",
"description" : "this is my description",
"priorities" : [
"one",
"two",
"three"
]
},
{
"slug":"slug2",
"description" : "this is another description",
"priorities" : [
"one",
"two",
"three"
]
}
]
}
In config.rb I have:
data.allgroups.groups.each do |h|
proxy "/groups/#{h.slug}.html", "/groups/gt.html", :locals => { :group => h }
end
Then in gt.html I have this :
<% h = locals[:group] %>
<div class="gt<%= h[:slug] %>">
<div class="gt-section">
<section class="main">
<p class="description"><%= h[:description] %></p>
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</section>
</div>
<div class="details">
<ul>
<% h[:priorities].each do |p| %>
<li>
<%= p %>
</li>
<% end %>
</ul>
</div>
</div>