Specify Ruby 2.0.0 in Gemfile
Format
Rename @attributes to @attribute_names

Rename @attributes to @attribute_names and @<something>_attributes to @<something>_attribute_names.
Rename @.._associations to @.._associaiton_names
Do not use before_filter to simply find a record
Custom form builder: do not select among >15
Fix GuestEntry-MembershipPurchase association
Use strings instead of symbols for params keys

Use strings instead of symbols for params keys in MembersController and InstructorsController.
Edit controller tests
Add controller tests
Remove some comments
Remove 'strong_parameters' gem

Using custom functions to process parameters seems more reasonable and flexible.
Process params for create/update in 2 controllers

Process attributes from params before using them for creating and updating records.  For now this is only done in MembersController and InstructorsController.
TODO comments for implementing params processing
Process params when creating/updating users
Update ERD diagram