Ensure that issue comments have associated issues and users.

db/migrate/20160822153115_create_issue_comments.rb

@@ -1,9 +1,9 @@
 class CreateIssueComments < ActiveRecord::Migration
   def change
     create_table :issue_comments do |t|
-      t.integer :issue_id
-      t.integer :commenter_user_id
-      t.text :body
+      t.integer :issue_id, :null => false
+      t.integer :commenter_user_id, :null => false
+      t.text :body, :null => false
       t.boolean :reassign
       t.timestamps :null => false
     end

db/structure.sql

@@ -691,9 +691,9 @@ ALTER SEQUENCE gpx_files_id_seq OWNED BY gpx_files.id;
 
 CREATE TABLE issue_comments (
     id integer NOT NULL,
-    issue_id integer,
-    commenter_user_id integer,
-    body text,
+    issue_id integer NOT NULL,
+    commenter_user_id integer NOT NULL,
+    body text NOT NULL,
     reassign boolean,
     created_at timestamp without time zone NOT NULL,
     updated_at timestamp without time zone NOT NULL