WIP integration and model testing

We're having problems with user model testing, it keeps giving us a nil class error for most of them.

We're also having problems with the integration test, it has the same error. 

Here are the errors:

UsersController
  .page
    should return the correct page number

User
  should have many karma_points
  #total_karma
    returns the total karma for the user (FAILED - 1)
  #full_name
    returns both the first and last names in a single string
  #valid?
    should require username to be set
    should ensure username has a length between 2 and 32
    should require first_name to be set
    should require last_name to be set
    should require email to be set
    when a user already exists
      example at ./spec/models/user_spec.rb:19 (FAILED - 2)
      example at ./spec/models/user_spec.rb:18 (FAILED - 3)
  .by_karma
    returns users in order of highest-to-lowest karma (FAILED - 4)
  .page
    should return the correct page number

pagination
  clicking page 1 (FAILED - 5)

KarmaPoint
  should belong to user
  #save
    increments the user's total_karma by the value of the karma point (FAILED - 6)
  #valid?
    should allow value to be set to 1
    should require label to be set
    should only allow numeric, integer values for value
    should allow value to be set to 0
    should require user to be set
    should not allow value to be set to -1

Failures:

  1) User#total_karma returns the total karma for the user
     Failure/Error: let(:user) { create(:user_with_karma, :total => 500, :points => 2) }
     NoMethodError:
       undefined method `+' for nil:NilClass
     # ./app/models/user.rb:31:in `update_karma'
     # ./spec/models/user_spec.rb:34:in `block (3 levels) in <top (required)>'
     # ./spec/models/user_spec.rb:37:in `block (3 levels) in <top (required)>'

  2) User#valid? when a user already exists
     Failure/Error: before { create(:user) }
     NoMethodError:
       undefined method `+' for nil:NilClass
     # ./app/models/user.rb:31:in `update_karma'
     # ./spec/models/user_spec.rb:16:in `block (4 levels) in <top (required)>'

  3) User#valid? when a user already exists
     Failure/Error: before { create(:user) }
     NoMethodError:
       undefined method `+' for nil:NilClass
     # ./app/models/user.rb:31:in `update_karma'
     # ./spec/models/user_spec.rb:16:in `block (4 levels) in <top (required)>'

  4) User.by_karma returns users in order of highest-to-lowest karma
     Failure/Error: user_med   = create(:user_with_karma, :total => 500, :points => 2)
     NoMethodError:
       undefined method `+' for nil:NilClass
     # ./app/models/user.rb:31:in `update_karma'
     # ./spec/models/user_spec.rb:25:in `block (3 levels) in <top (required)>'

  5) pagination clicking page 1
     Failure/Error: generate_users
     NoMethodError:
       undefined method `+' for nil:NilClass
     # ./app/models/user.rb:31:in `update_karma'
     # ./spec/support/generate_users.rb:4:in `block in generate_users'
     # ./spec/support/generate_users.rb:3:in `times'
     # ./spec/support/generate_users.rb:3:in `generate_users'
     # ./spec/features/users_spec.rb:8:in `block (2 levels) in <top (required)>'

  6) KarmaPoint#save increments the user's total_karma by the value of the karma point
     Failure/Error: let(:user) { create(:user) }
     NoMethodError:
       undefined method `+' for nil:NilClass
     # ./app/models/user.rb:31:in `update_karma'
     # ./spec/models/karma_point_spec.rb:18:in `block (3 levels) in <top (required)>'
     # ./spec/models/karma_point_spec.rb:23:in `block (3 levels) in <top (required)>'

Finished in 0.59472 seconds
22 examples, 6 failures

Failed examples:

rspec ./spec/models/user_spec.rb:36 # User#total_karma returns the total karma for the user
rspec ./spec/models/user_spec.rb:19 # User#valid? when a user already exists
rspec ./spec/models/user_spec.rb:18 # User#valid? when a user already exists
rspec ./spec/models/user_spec.rb:24 # User.by_karma returns users in order of highest-to-lowest karma
rspec ./spec/features/users_spec.rb:11 # pagination clicking page 1
rspec ./spec/models/karma_point_spec.rb:20 # KarmaPoint#save increments the user's total_karma by the value of the karma point