Toy cipher -- does it have a name?
This is a simple substitution cipher, specifically a mixed/deranged alphabet cipher. See wikipedia's description:


  Substitution of single letters separately—simple substitution—can be demonstrated by writing out the alphabet in some order to represent the substitution. This is termed a substitution alphabet. The cipher alphabet may be shifted or reversed (creating the Caesar and Atbash ciphers, respectively) or scrambled in a more complex fashion, in which case it is called a mixed alphabet or deranged alphabet. Traditionally, mixed alphabets may be created by first writing out a keyword, removing repeated letters in it, then writing all the remaining letters in the alphabet in the usual order.
  Using this system, the keyword "zebras" gives us the following alphabets:


 Plaintext alphabet:    ABCDEFGHIJKLMNOPQRSTUVWXYZ
Ciphertext alphabet:    ZEBRASCDFGHIJKLMNOPQTUVWXY