WIP: Render database schema using Mermaid.js

Still need to:
* Move mermaid.js to static files
* Make template for mermaid wrapper
* Create new page for SQL viewer then add explorer

db.py

@@ -10,6 +10,7 @@ from features.calendar import Calendar
 from features.exercises import Exercises
 from features.stats import Stats
 from features.workout import Workout
+from features.sql_viewer import SQLViewer
 from utils import count_prs_over_time, get_all_exercises_from_topsets, get_exercise_graph_model, get_stats_from_topsets, get_topsets_for_person, get_weekly_pr_graph_model, get_workout_counts, get_workouts
 
 
@@ -19,6 +20,7 @@ class DataBase():
         self.stats = Stats(self.execute)
         self.workout = Workout(self.execute)
         self.exercises = Exercises(self.execute)
+        self.sql_viewer = SQLViewer(self.execute)
         db_url = urlparse(os.environ['DATABASE_URL'])
         # if db_url is null then throw error
         if not db_url: