adds rel canonical on show views

app/views/budgets/groups/show.html.erb

@@ -1,3 +1,7 @@
+<% content_for :canonical do %>
+  <%= render "shared/canonical", href: budget_group_url(filter: @current_filter) %>
+<% end %>
+
 <div class="expanded budget no-margin-top">
   <div class="row">
     <div class="small-12 medium-9 column padding">

app/views/budgets/investments/index.html.erb

@@ -4,6 +4,9 @@
              search_path: budget_investments_path(budget_id: @budget.id, page: 1),
              i18n_namespace: "budgets.investments.index.search_form" %>
 <% end %>
+<% content_for :canonical do %>
+  <%= render "shared/canonical", href: budget_investments_url(@budget, heading_id: @heading.id, filter: @current_filter) %>
+<% end %>
 
 <main id="budget-investments-main">
 

app/views/budgets/investments/show.html.erb

@@ -1,4 +1,7 @@
 <% provide :title do %><%= @investment.title %><% end %>
+<% content_for :canonical do %>
+  <%= render "shared/canonical", href: budget_investment_url %>
+<% end %>
 
 <%= render partial: '/budgets/investments/investment_show', locals: {
   investment: @investment,

app/views/budgets/show.html.erb

@@ -1,3 +1,7 @@
+<% content_for :canonical do %>
+  <%= render "shared/canonical", href: budget_url(@budget, filter: @current_filter) %>
+<% end %>
+
 <div class="expanded budget no-margin-top">
   <div class="row" data-equalizer data-equalizer-on="medium">
     <div class="small-12 medium-9 column padding" data-equalizer-watch>

app/views/debates/show.html.erb

@@ -1,4 +1,8 @@
 <% provide :title do %><%= @debate.title %><% end %>
+<% content_for :canonical do %>
+  <%= render "shared/canonical", href: debate_url(@debate) %>
+<% end %>
+
 <% cache [locale_and_user_status(@debate), @debate, @debate.author, Flag.flagged?(current_user, @debate), @debate_votes] do %>
   <div class="debate-show">
     <div id="<%= dom_id(@debate) %>" class="row">

app/views/proposals/show.html.erb

@@ -5,6 +5,10 @@
             social_title: @proposal.title,
             social_description: @proposal.summary %>
 <% end %>
+<% content_for :canonical do %>
+  <%= render "shared/canonical", href: proposal_url(@proposal) %>
+<% end %>
+
 <% cache [locale_and_user_status(@proposal), @proposal, @proposal.author, Flag.flagged?(current_user, @proposal), @proposal_votes] do %>
   <div class="proposal-show">
     <div id="<%= dom_id(@proposal) %>" class="row">