Merge pull request #27 from feministy/bugfixes

bugfixes
do not calculate balance or pending_balance unless ta is approved
new condition for saving only if the TA is approved
nesting information about hours for approved TAs only
saving 0 for credit hours for non-approved TAs
clean up the pending TA view on the private page
Merge pull request #28 from feministy/approved_ta_credits

only approved TAs can accumulate credits
ui stuff from ember branch - minus layout
toggle icons
nest input inside of modal
add submit type to button styles
fix num_tas_still_needed, add num_tas
admin dashboard ui vastly improved, also has some fancy js toggle
notes and remove prefix
comment out the custom param for now
route for ta list
ta_list partial - a little hacky but whatevs
styles for typography, buttons, card, spacing to apply to admin dashboard and partial pop ups
fix ta count - again
pretty popup for admin dashboard