title: Django model doesn't generate sql when the model name is similar to the filename?
body: <p>I'm writing an django app called <strong>comments</strong>, but sth. error when I use the model <strong>Comment</strong>.</p>
  
  <p>I run following command and find that <strong>Comment</strong> doesn't generate sql.</p>
  
  <pre><code>python manage.py sqlall comments
  </code></pre>
  
  <p>part of output:</p>
  
  <pre><code>BEGIN;
  CREATE TABLE "django_comments" (
      "id" integer NOT NULL PRIMARY KEY,
      "content_type_id" integer NOT NULL REFERENCES "django_content_type" ("id"),
      "object_pk" text NOT NULL,
      "site_id" integer NOT NULL REFERENCES "django_site" ("id"),
      "user_id" integer REFERENCES "auth_user" ("id"),
      "user_name" varchar(50) NOT NULL,
      "user_email" varchar(75) NOT NULL,
      "user_url" varchar(200) NOT NULL,
      "comment" text NOT NULL,
      "submit_date" datetime NOT NULL,
      "ip_address" char(15),
      "is_public" bool NOT NULL,
      "is_removed" bool NOT NULL
  )
  ;
  CREATE TABLE "django_comment_flags" (
      "id" integer NOT NULL PRIMARY KEY,
      "user_id" integer NOT NULL REFERENCES "auth_user" ("id"),
      "comment_id" integer NOT NULL REFERENCES "django_comments" ("id"),
      "flag" varchar(30) NOT NULL,
      "flag_date" datetime NOT NULL,
      UNIQUE ("user_id", "comment_id", "flag")
  )
  ;
  ...
  
  CREATE TABLE "comments_url" (
      "id" integer NOT NULL PRIMARY KEY,
      "content" varchar(64) NOT NULL,
      "url" varchar(2048) NOT NULL
  )
  ;
  CREATE TABLE "comments_commentboard" (
      "id" integer NOT NULL PRIMARY KEY,
      "title" varchar(64) NOT NULL,
      "url" varchar(2048) NOT NULL
  )
  ;
  CREATE INDEX "django_comments_37ef4eb4" ON "django_comments" ("content_type_id")
  ;
  CREATE INDEX "django_comments_99732b5c" ON "django_comments" ("site_id");
  CREATE INDEX "django_comments_6340c63c" ON "django_comments" ("user_id");
  CREATE INDEX "django_comment_flags_6340c63c" ON "django_comment_flags" ("user_id
  ");
  CREATE INDEX "django_comment_flags_3925f323" ON "django_comment_flags" ("comment
  _id");
  CREATE INDEX "django_comment_flags_9f00eb17" ON "django_comment_flags" ("flag");
  
  
  COMMIT;
  </code></pre>
  
  <p>part of models.py:</p>
  
  <pre><code>from django.db import models
  from django.contrib.auth.models import User
  import datetime
  
  ...
  
  class Url(models.Model):
      content = models.CharField(max_length=64)
      url = models.URLField(max_length=2048)
  
      def __unicode__(self):
          return self.content
  
  class Comment(models.Model):
      title = models.CharField(max_length=64)
      comment_str = models.CharField(max_length=128)
      #desc = models.CharField(max_length=64)
      #comment_board = models.ForeignKey(CommentBoard)
  
      #def __unicode__(self):
      #    return self.title + ':' + self.content
  
  class CommentBoard(models.Model):
      title = models.CharField(max_length=64)
      url = models.URLField(max_length=2048)
  
      def __unicode(self):
          return self.title
  </code></pre>
  
  <p>When I rename Comment to Comment123, then it works. But I guess it's a limitation
  I don't know before. Could anyone tell me why is it?</p>
  
  <pre><code>CREATE TABLE "comments_url" (
      "id" integer NOT NULL PRIMARY KEY,
      "content" varchar(64) NOT NULL,
      "url" varchar(2048) NOT NULL
  )
  ;
  CREATE TABLE "comments_comment123" (
      "id" integer NOT NULL PRIMARY KEY,
      "title" varchar(64) NOT NULL,
      "comment_str" varchar(128) NOT NULL
  )
  ;
  CREATE TABLE "comments_commentboard" (
      "id" integer NOT NULL PRIMARY KEY,
      "title" varchar(64) NOT NULL,
      "url" varchar(2048) NOT NULL
  )
  ;
  </code></pre>
  
  <p>Should I not use <strong>Comments</strong> as app-name and <strong>Comment</strong> model at the same time?</p>
  
  <p>Can anyone tell me where to find the limitation?</p>