Added specification of different types of key

Definitions an examples of 4 types of unique keys are logged
Vocabulary file added, database Lecture 2 finished

Added file with a sample of data format for vocabulary, added a few
vocabularies. Database lecture notes updated to “Lecture 2 finished”.
Added file to record things to learn.
finished rails tutorial No. 12

Finished rails tutorial No. 12
learned and have setup command lines for text wrangler
Static pages building method learned

Learned how to build static and slightly dynamic pages.
Updated a little other files as well