prevent update if template is in use

app/controllers/contract_templates_controller.rb

@@ -5,8 +5,9 @@ class ContractTemplatesController < ApplicationController
 
   layout 'project'
 
-  before_action :set_project, except: [:destroy, :edit]
-  before_action :set_contract_template, only: [:destroy, :edit]
+  before_action :set_project, except: [:destroy, :edit, :update]
+  before_action :set_contract_template, only: [:destroy, :edit, :update]
+  before_action :set_project_from_contract_template, only: [:edit, :update]
   before_action :show_splash_screen, only: :index
 
   def index
@@ -33,7 +34,21 @@ class ContractTemplatesController < ApplicationController
   end
 
   def edit
-    @project = @contract_template.project
+    @release_type = @contract_template.release_type
+  end
+
+  def update
+    unless @contract_template.editable?
+      redirect_to([@project, :contract_templates], alert: t('.error')) and return
+    end
+
+    @contract_template.attributes = contract_template_params
+
+    if @contract_template.save
+      redirect_to [@project, :contract_templates], notice: t('.notice')
+    else
+      render :edit
+    end
   end
 
   def destroy
@@ -43,6 +58,10 @@ class ContractTemplatesController < ApplicationController
 
   private
 
+  def set_project_from_contract_template
+    @project = @contract_template.project
+  end
+
   def show_splash_screen
     render :splash if contract_templates.non_archived.count.zero?
   end