Update merchants.yml

Added Infield loan services. Source was PM following this post:
https://redd.it/4wfu0o

_data/merchants.yml

@@ -54,6 +54,8 @@
   merchants:
     - name: California Fintech Network
       url: https://www.californiafintech.org/plans/
+    - name: Infield Loan Services - Atlanta, Construction Consulting, Contract review, Feasibility, Funds Escrow
+    url: mailto:[email protected]
     - name: CryptoEscrow Escrow Service
       url: http://www.cryptoescrow.eu
     - name: Cryptostorm VPN
@@ -61,7 +63,7 @@
     - name: Esperanto lessons from Kaja
       url: mailto:[email protected]
     - name: Guitar Music Theory course w/ 30% XMR discount
-      url: http://guitartheoryrevolution.com/
+      url: http://www.guitartheoryrevolution.info/blog/guitar-theory-revolution-store/
     - name: MyMonero Web-based Wallet
       url: https://mymonero.com
     - name: Pradeep Atluri, Psychiatrist, New York