[closes #3] Added skill and category system

[refs #3] added skill model; setup paper trail helpers for tests

[refs #3] added gemnasium badge; updated dependencies

[refs #3] Patched paper trail to allow creating of versions in past

[refs #3] setup drb test with spork-minitest, 50% boot time cut

[refs #3] Added basic skill controller, just index

[refs #3] added tests for skill controller

[refs #3] updated readme

[refs #3] added refutes

[refs #3] added port feature to procfile

[refs #3] Added simple bar chart to start off

[refs #3] updated travis config

[refs #3] Added ability to assign skills and to edit them

[refs #3] Removed abusive usage of before_{filter,action}'s

[refs #3] Added ability to remove skills

[refs #3] Added right permissions on skill actions

[refs #3] Appropriate visibility to edit & destroy links

[refs #3] skill names and categories most frequent scopes

[refs #3] Added dropdown with the most used skills and categories

[refs #3] Added typeahead for name and category

[refs #3] fixed dropdown events

[refs #3] Styled dropdown to fit

[refs #3] In the middle of styling range

[refs #3] Styled out range for good

[refs #3] Added descriptive labels to set skill by click

[refs #3] Added nice chart for skill history

[refs #3] fixed style loading; added no-skill-history alert

[refs #3] Added control to each mate to access skill list

[refs #3] Added graphical representation for skill levels on skills page

[refs #3] Added skill category crunching

[refs #3] Added category avg rates at profile page with graphic
representation

[refs #3] Added list of memberships