implement amendment signing

app/controllers/public/amendments_controller.rb

@@ -0,0 +1,44 @@
+class Public::AmendmentsController < Public::BaseController
+  skip_after_action :verify_authorized, :verify_policy_scoped
+  before_action :set_account, :set_project, :set_contract_template, :set_release
+
+  def new
+    if @release.amendment_signed?
+      render :create, locals: { already_signed: true }
+    end
+  end
+
+  def create
+    @release.amendment_signer_name = release_params[:amendment_signer_name]
+    @release.amendment_signature_base64 = release_params[:amendment_signature_base64]
+    render :new unless @release.save
+  end
+
+  private
+
+  def release_params
+    release_type = @contract_template.release_type
+    param_name = "#{release_type}_release".to_s
+    params.require(param_name).permit(:amendment_signer_name, :amendment_signature_base64)
+  end
+
+  def set_release
+    release_type = @contract_template.release_type
+    param_name = "#{release_type}_release_id".to_s
+    release_id = params[param_name]
+
+    @release = @contract_template.releases.find(release_id)
+  end
+
+  def set_contract_template
+    @contract_template = @project.contract_templates.find(params[:contract_template_id])
+  end
+
+  def set_project
+    @project = @account.projects.find(params[:project_id])
+  end
+
+  def set_account
+    @account = Account.find_by(slug: params[:account_id])
+  end
+end